Sorry about the title if it reads a little confusing. I didn't know how to phrase it.

I have a younger male pastel that turned a year last fall. He has always been a picky eater and is only around 600 grams. I have paired him with an adult female and for the most part he is not interested. (Can't really say the female is either) I have accepted the fact that he just isn't ready yet and am ok with this. My question is on the female:
Is there a window of opportunity with a female during the breeding season? Meaning if I keep trying with my young male and he does not breed her, will she eventually go through the process and end up absorbing the folicles if she does not have viable sperm?
I would hate to lose an opportunity with her and I do not want to use multiple males. (I really want to see (and know) this males offspring)
So . . . would there be a time where I should stop with my small male and use another one? (I know, this is essentially using multiple males, but there is a good chance he has not bred her.)

The above all makes sense to me, I hope it does for you

Thanks

Jim