first, there is nothing wrong with flirting with someone you're attracted too. the definition of flirting is "Attention without intention." Living in the gay part of town in seattle, i flirt with straight guys all the time, and it's all just good fun and they know it and it's not a problem.
second, there's also nothing wrong with flirting with younger guys. Their reaction will let you know if they are receptive or not. the point of flirting is not to take anything that happens personally (see the definition above). there are a ton of younger guys who like the idea of hanging with an older guy, either for friendship of for more. I have one young friend who is 18 and he and i have a mentor/protege friendship that is quite nice for both of us.
I really like that you just wanna ease into this transition. You seem like you're being very smart about it. Too bad you're in Texas--i'd go out for coffee or lunch with you in a heartbeat (yes, i'm flirting with you).
