As a slime, your lack of internal organs means less squishy things to worry about. Your Constitution and Strength scores each increase by 2.
However, as a slime, you may have difficulty with social cues and common knowledge required to function in society. Your Intelligence and Charisma scores each decrease by 2.

If you are using the optional rules for flexible modifiers, you may place these modifiers in any stat you with, as long as they do not overlap. Alternatively, instead of reducing two scores by 2, you may choose to subtract 1 point from all scores not increased by this feature.

You can speak, read, and write Common and one other language of your choice.

Slimes absorb everything around them, and this extends to tool use. You gain proficiency in a tool of your choice, and that tool is permanently integrated into your body, appearing and disappearing at will.  You double your proficiency bonus for any ability checks you make with it.

You gain 30 ft of Blindsight.

Being made of ooze, your body is naturally resistant to poison. You have advantage on saving throws against poison, and you have resistance against poison damage.

You're a slime. You're a girl. You're a slimegirl. Your type is both Ooze and Humanoid.

Due to your amorphous nature, you may squeeze through spaces as small as 6 inches by 6 inches without risk to your neurological structures. Any smaller, and you risk either amnesia or what wizards have dubbed the "cheese-grater effect."

Your base walking speed is 30 feet.

Slimes are generally built like humans, standing anywhere from 4 feet to over 6 feet tall. Your size is Medium. 

Independent and self-reliant, Slimegirls tend toward a neutral alignment. With no knowledge of societal norms, their actions tend towards the chaotic spectrum.

Slimes age with experiences, not time. Memories are constantly gained and lost by the shifting of a slime's goopy body, and your increased intellect (compared to other slimes) does little to mitigate this.

As slimes can continue to grow and expand indefinitely, your maximum age is unknown.  However, Slimegirls generally achieve a preferred body image within one or two years of becoming sentient.