As a cleric, can I cast a cantrip followed by a spell?

Playing the game I cast sacred flame (cantrip, 1 action) and then I asked if I could use my bonus action to cast spiritual weapon.  Is this allowed or not.  I thought if you cast a cantrip then you can cast any spell as a bonus action (provided it has the bonus action attribute).

I was told I should have cast the bonus action then the cantrip.  Is this right? What difference does it make?

If you are using the 24 rules, you can only cast 1 spell with a spell slot per turn. As sacred flame is a cantrip and does not use a slot, you can do this, yes. The order does not matter.

In 14, the rules are slightly different, If you cast a spell with a bonus action, you can only cast a cantrip on the same turn. They effectively get you to the same place in this situation. And once again, order doesn't really matter.

FYI The relevant rules can be found here:

For D&D 5E (2014) https://www.dndbeyond.com/sources/dnd/basic-rules-2014/spellcasting#BonusAction

Bonus Action

A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven't already taken a bonus action this turn. You can't cast another spell during the same turn, except for a cantrip with a casting time of 1 action.

For D&D 5.5E (2024) https://www.dndbeyond.com/sources/dnd/br-2024/spells#OneSpellwithaSpellSlotperTurn

One Spell with a Spell Slot per Turn

On a turn, you can expend only one spell slot to cast a spell. This rule means you can’t, for example, cast a spell with a spell slot using the Magic action and another one using a Bonus Action on the same turn.