Thomas, what kind of relationship are you imagining when you are picturing this?
I think that most people (there are going to be exceptions) care more about emotional maturity than physical maturity. How well do you feel you know what you want out of a relationship, what your boundaries are, how willing you are to respect others' boundaries.
Please check out The Birdcage - an open, friendly Polyamory forum for all parts of New York State
"Listen, or your tongue will make you deaf." - Native American Proverb