Bit of advice for you, from my own experience...
I, like you, have a preference to fuck women in the 20 - 30 age range, tend to be in better shape, more attractive to my tastes. They are generally a worse punt, especially if you are not experienced.
Older MILF types, I am less attracted to, but have had some of my best, most natural and intimate punts with those types of providers.
I reckon they'd be most likely to take it easy on you, explain the situation and you will probably enjoy yourself.