Harley - just something to consider - if you don't spay your cat and she isn't mated you may well find that she will start spraying around your apartment. By not spaying her and not mating her you will, in the longer term, be doing her more harm than good and also if she becomes frustrated her temperament may change and she may become destructive.

Having her spayed is not forcing her not to be a cat - it is showing you are taking responsibility (something you have obviously already done by taking her in) and that you have her best interests in mind health wise.

The other thing to consider is that having/raising a litter of kittens doesn't come cheap and whilst they are wonderful it is hard work and are you prepared for the heartache if you lose a kitten or two?

Spaying is perfectly safe nowadays and the cats recover very quickly and are much happier for it.