When we got our first minis we were told to breed them at 2. I bred two of them once, and swore I would never do that again. My ignorance could have caused issues for both, fortunately the one didn't take/absorbed. The other I have never rebred for a variety of reasons.
I bred some of our 3 yr olds last year, but I'm really heading towards first breeding at four/five. This give us sufficient time for showing, working with the horse, and allows them to be fully mentally/physically mature. I won't discount breeding a 3 yr old again, but at this point I don't see the need for us. (I am speaking about mares as a stallion I would test at 3 yrs and have tested 2 yr olds in the past.)
It really is a personal decision, and you can always consult your vet for a pre-breeding exam (a good idea with narrow hipped mares), to get his/her opinion too.
BTW - there are no stupid questions! It would be stupid not to ask!