It amazes me how in depth (or appearing in depth) many of the written campaigns are. But I also would like to make plots of my own. And earlier today, I began working on a pretty simple and even cliche plot for my first written campaign. Basically, a typical fantasy Kingdom has been taken over by a typical evil Empire who massacred most of the Royal Family, save one of course. And now, years later, a group of heroes rise of to challenge the Empire and free the Kingdom. Right now, I'm trying to decide if there's a rebellion going on that's lead by the last Prince or Princess of this Kingdom, or if the quest involves finding the last heir. Which do you think is better? The heroes get caught in a revolution? Or they must find the last remaining member of the Royal Family? Again, really cliche, but do you think this is a good way to start as a DM?

Clichés are clichés for a reason: they are easy to tell, and often work well. Starting simple is the best way to start for a DM, and a plot does not have to be super original or complex to be engaging. An easy way to make it more interesting is adding a twist. For example, maybe the rebellion is led by the heir of the kingdom in secret, who was denied a place in the royal succession and rose up in response. And they gathered a party loyal to the old kingdom to find as many loyalist as they could, to execute them and suppress revolt. 

Yes, I think so. Great starting point. Either of the two options.

First, the flipside of "cliche" is "classic". It's done a lot because it works. It's a fun plot to play through. Sure, you don't want to keep doing the same thing over and over, but for your first campaign, you're NOT "doing it over and over" - it's literally your first time!

Second, because the players are likely to derail the plot in many exciting ways. That's what players do. If you start with something simple, it's easy to adapt it if the players do something weird. Whereas if you do some complicated counterintuitive thing, it might be harder to adapt it on the fly. Let the players subvert the cliche if they want, or play it straight if they want.

I've already got a twist. Turns out the last heir is a product of a eugenics experiment. Turns out the last Queen of the Kingdom was not so good as we thought. She also wanted to build an Empire, and agreed to partake in an experiment to create a human with magic abilities to rival the Gods. So she collaborated with the Emperor and had their children put into an arranged marriage. The deal was the new Prince or Princess would be brought to the Empire for their training, but somthing unexpected happened. The Queens direct heir contracted a fatal illness and passed away, so the heir was now the Queen's grandson or granddaughter. So the Queen backed out of the deal. And that's what lead to the invasion and occupation. There's still a lot of work to do though.

i copy others work all the time. as long as you change it enough to not be so blatantly obvious to the players, you should be able to come out of there on top.
its actually what WotC has done with their actual adventures. their codenames ranges from alice in wonderland to hellraiser. they don't care as long as it gives them the theme they want to go for.

exemple of an adventure i did to my players...
the mayor of a city calls for adventurers to rescue his missing daughter. he pays a lot for her return and give out a bonus reward if they bring back the head of the bandit lord that kidnapped her. the adventurers go to the forest, starts attacking the kidnappers hideout and find the bandit lord waiting for them with two sabers up. they duke it out, until the little girl comes running out of the second floor forest town yelling, DONT HURT HIM DON'T HURT HIM, FATHER STOP!!! all the players stops and yell what the... the whole fight comes to a stop. the bandit lord tells the little girl to stay away, he will deal with them and then he will tell your grand father in person that he will never take her back from him ! girl eventually tells the players that her mother is sick and thats why she wanted her daughter to live with her father. but her grandfather wouldn't let her leave, so she had to sneak out of the city.

now where did you ever see this story ?
surely not in stallone Over the Top movie !!!
the only person who ever caught onto it was my cousin who had seen the movie too. one of the best stallone movie to me.
but then again, he only realised it at the end when the girl yelled father... now he realised... a big rich old man, a girl missing, a wife being sick... it stuck to him, but it was too late, we were at the end of that adventure. he looked at me, clapped his hands and said... FOOLED ME !!!

that's all it is...
you love wolverine, do it... create wolverine... but instead of claws it could be shortswords, instead of being a human, he could be a gnome, why not thats different.
don't name him logan, name him something else. that'S the point... change the key part to something else. keep the overall story, but make your characters your own. in my exemple... the city mayor was the old man int he movie, but the old man was a business man, not the mayor. in th emovie, the father kidnaps the boy, well not kidnap, just took him from his school after school. in my campaign the child ran off. but the grand father passed it for a kidnapping cause he wanted the father dead. another point, in the movie  the grand father only wants the guy to disappear, no bloodshed or anything. in my story, it became vengeance from the old man, he wants him dead, he has enough of him being the bandit lord. all those are changes that made my players unaware that they were reenacting a movie i love. my cousin watched that movie a bazillion times too... and even him was fooled until the very end when it all clicked to him.

thats all writing a story is. originality is a luxury nobody really have. everything has been done over and over again. but that doesn't mean we can't have our own visions of the same things.

Simply and unambiguously put: yes, do that. 

Your plots can come together over time, there's no problem with relying on classic tropes, even clichés, as you're starting out. Odds are your players will still love it too.