She should be 17/18 I think she is a good strong leager for Aladdin

Though she was officially stated as 15, I think she's more like 17-18 years old than 15.

She isn't 15. That is only a fan theory. There is no information about her age but once they said she is 17 turning 18 in the 1st movie. If I remember well the movie's director said that.

They NEVER state her actual age. The only thing the Sultan says is "by your next birthday" "you've only got three days!" I can't recall at any moment where her actual age is stated, and I'd prefer for the movies to say their ages (like with Aurora, Ariel or Rapunzel) or give confirmative guesses (i.e.. like Tiana, we know she's of age otherwise she wouldn't work) over what any rando on the Internet says.

She always seemed more like 17/18. At the most maaaybe 16? 15 year olds don't look at all like her (then again, Aurora doesn't resemble physically any sixteen year old, but whatever).

She looks like she should be 16 or 17 at the youngest.

Her age has been confirmed. The makers of the movie wanted her to be 15 going to 16 in the movie, but they remembered the flack Ariel got for marrying at 16. So in the scene where her age was said by the sultan, instead of the line being "by your 16th birthday" it was changed to "by your next birthday." It's not a fan-theory but common knowledge for a reason.

I don't care what the fan theory or official statement says. She'll always be 17/18 to me.

This makes Jafar´s actions towards her EVEN more creepy

Although I think she's closer to sixteen.