There is a thread about this right now.
http://www.ball-pythons.net/forums/s...ad.php?t=54943
Since you got her from a pet store, there is no way to know what she is. She could be het for something and the people who sold her to the pet store just didn't bother to pass along that information. Especially if she only had a low chance of being het, that is likely that info wouldn't be passed on to the pet store.
It is also possible she is CH or WC. If so, who knows what genetics she has. She might even carry something new that no one has seen before (extremely unlikely but possible).
The biggest problem is you have no idea what she'd be het for even if she is het for something. So if/when you breed her, you'll have to decide if it is worth it to breed her offspring back to her to try to prove something out, and how many years you'll devote to that. Even if she is het, her offspring will only have a 50% chance of het, so you'd have to breed at least 2 different sons back to her before you'd even be close to being confident she doesn't carry something.
In the meantime, you could be breeding her to a pastel or other co-dom and getting 50% morph babies each year. Or a super pastel or other super and get 100% morph babies each year.
I guess you can kind of do both at the same time by breeding her to a super something the first time, then each year after her babies get big enough, breed her to a different one of her sons and you'll still be getting 50% morphs out of her. But you'll also be inbreeding (or line breeding I guess technically) which should be avoided when possible, for an extremely small chance that she carries something.
Most people would say if you want to breed for morphs, buy snakes that you know carry the gene or at least a high % chance of being het. But there have been 2 stories on bp.net this year of people who hatched out totally unexpected morphs, so it does happen.