No I started at thirteen and roleplaying helped shape who I am as a person today. I learned a lot of stuff from jerks and friends alike that I hold myself to not repeat, or imitate today. However you must understand some people WILL call you out on things and that you can't be a special little snowflake just because of your age. Everyone should be held accountable for what they say and do to an extent. If you can measure up to your peers on this site or in real life then as Kamina in Gurenn Lagann says, "Burst through the ceiling into the surface' and just get better as it goes on. 

However to answer your question you really shouldn't poke your head into threads looking for a more mature partner for roleplaying unless they're aware of the age difference and they're willing to play with you. 

But that's just my two cents.