Learned at 18. I loved biking everywhere and was against cars for environmental reasons. Also I didn't have a car. Eventually I wanted to learn because taking 3 hours on transit for a 30 min drive was starting to get annoying.

My dad mostly taught me, but he was not always a patient teacher tbh. But it worked. I had to go to drivers ed class where they teach you stuff you already probably know. I had to take some in-car drives with an instructor, and I don't think they were that interesting either. The instructor found out I liked to ride bikes, so he took me to a road where I would have to learn how to pass cyclists, so that was cool I guess.

I failed the test the first time. I was nervous and the instructor was ornery and stressed me out more. I was trying to parallel park a van and I couldn't do it within the time limit.

The second time I got a really chill instructor, and when I was having trouble parking he was like, its OK, you got this, and I was able to do it within the time limit. Also I had practiced a bit more too.

18 is not too old to learn how to drive. I recommend you take your time and get a lot of practice.