We have two female pits, one around 2 y/o and the other around 1 y/o. They’ve gotten into a few little tussles, mostly because the younger one is overzealous, but for the most part they get along great. They sleep together all day, they walk together great, etc. If you get a second dog, regardless of the breed, plan on doubling the amount of time and effort you put into your animals now. If you are willing to do that, you can handle it and it will be worthwhile.
Glad your parents turned you on to this wonderful breed! I love having people over and giving them a chance to interact with our pits. All of their preconceived notions go right our the window and they fall in love!