The thing about making it is that age is totally irellevant if you don't have a family.
Work 8 hours, commute 2 hours, eat 1 hour. That's still 5 fucking hours left to draw every single day of the week. except weekends.
The question then is, Do you want it bad enough? Because if you don't then you could be 19 or 65 and you still wouldn't make it.
If you would like to do other things than: Sleep, Eat, Work, Study you won't fucking make it. Throw networking into that mix once you get good enough because oppertunities need to be sought, earned and eventually you do want to put your dick into another human being. That's just a nice change of pace...
Fuck it guys, You are the only ones stopping yourself from getting there. You could be a professional right now, it's all in your head.
Nothing is physically preventing you from painting at a professional level. It's all knowledge and mental blocks.
Go for it, At 25 you still have 40 years left of your professional career, thats 35 years to work as a Artist rather than something else.