To "hook" Muffin up or not

Muffin is in heat. Every time one of the dogs goes in heat I debate whether I should let them get pregnant or not. So far, I never have. But I need to make a decision quickly regarding Muffin. She is THEE BEST dog we have ever had. She never makes a peep, she doesn't bark, she has good hair, and her temperment is just the sweetest. This is her 2nd cycle, so if I don't mate her, I need to get her fixed. We'll be moving in 3 months and do I REALLY want to be dealing with puppies?

I've never had a dog have puppies. Is it easy? Is it hard? Will this change her into a crabby mom like me? Or will she stay her sweet self?

I need advice - STAT!

What to do...what to do???