I don't think you can answer the question by focusing only on the issue of
flaps. A better question is "How many new and different things will my
first glider have that I am not experienced with?" If the answer is only
"just flaps" - no big deal. If it's flaps plus things like no spoilers/90
degree flaps, or a drogue chute, or side mounted stick, or V tail, or large
span - then you have to be very careful that you are not over extending
yourself. My first glider did not have flaps (Phoebus B) - my son's did
(ASW-20). Both were good choices I think.

Good luck

Roy