You're only 25 - you're good to go!!! For those of us that are a bit passed the 25 mark by 20 years or more wish we started what we are doing now when we were 25 :-).
The real difference I think when you start as a teenager is that you have a lot more disposable time. I can remember my friend in high school spending his entire summer in his room playing his guitar. Needless to say, he was pretty darn good! I had a summer job and wasn't quite as obsessed as he was, so I didn't advance as quickly.
Once you get older and have to get a job, have a family, and all of the obligations that come along with that, time becomes a scarce.