Yes maturity is not always linked to age but what you do not realise (and I am assuming you are still at school) that you will grow and mature heaps in your first few years in the big wide world. You do not realise at 16/17 how little you know about the world and responsibility until you are thrust into it. I know it sounds like I am not much older than you but I have been out of school for over a year and let me tell you at 17 I THOUGHT I was mature but I can assure whilst I was more mature than most 17 year olds I was not as mature as someone who had been out of school.
The age gap you are talking about sounds like you'd be in different places in your lives. You are studying, perhaps preparing for tafe, uni, an aprenticeship or your first real job. He probably already has his own job, assets etc...also wants to go out clubbing, drinking or maybe even ready to settle down.
There are mature guys out there closer to your age, I am 19 going out with a 21 year old. He is more mature than me without being a decade older. I met him a few months out of school and I had a great deal of maturing to do as a person.
Working, studying at teritary level and spending time out in the adult world will mature you, just be wary he has more life exerience than you, the relationship may be tough if you want different things or cant do things because of age/study restraints that he wants to do.
Whilst I believe age should not be a huge factor in a relationship that is a big gap and I think you are at different points in your lives.
If you really think it can work than go for it, but be wary of much of the useful advice in this thread and be prepared to have to grow up fast if you want to continue dating someone 10 years older. I had to grow up fast with someone two years older and really I know it wasnt the age that made the difference it was all the life experience he had!
Good luck and you are free to take this as you want