How old do you have to be to become a limo driver?

I am thinking of becoming a limousine driver when i am 16, but i don't know how old you have to be. I am gonna make my own limo company of like 1 person, so i don't have to worry about being hired. Plus if i am 16 or under 21 then can i have my dad stock the back with boos( Wine, beer, etc.) for like weddings and for other people over 21. Plus i am wondering if there are any laws for putting extra stuff in the back like plasma screen tvs, min fridges, etc. I live somewhere in Pennsylvania and i am in a very good location that people always gets married at, and there is a lot of rich people around me. And would there be any law for me adding anything on the inside?