I fancy doing a spot of time trialling, but not to the extent of buying a TT bike. I'd hardly use it.
When I did the London-Surrey 100 last year, I averaged a shade over 20mph for the first 40 miles, and a little under for the next 60. That's on a B'Twin Triban 500SE, with nobody helping me out, riding well within myself as I didn't know how much the ride would take out of me.
I'm pretty confident that on a 10-mile flattish TT in good weather, I could do 25-27mph if I emptied the tank.
I'm 49, and I really don't make any claims to be a great cyclist, or even a particularly good one. If there were an SI Unit for being bog-average at everything, it'd be called the "Dec66".
I think the OP has a bit of a way to go to get to semi pro status... But I'm not going to discourage him. If you don't buy a ticket, you don't win the raffle.