Good job in making an effort to ask her out.
Did she specifically tell you that she would hang out with you but not go out on a date with you? If so, she may have a boyfriend or may not be interested in you romantically.
It would be a good idea to ask for her number the next time that you see her.
If she doesn’t volunteer it, she may have simply agreed to hang out with you just to be polite. If she does volunteer it, then you should engage in phone conversation with her soon after and ask her out on a proper date.
This will keep you from wasting your time with a girl who may only want to hang out with you as a friend and nothing more.