What does this mean? Purity ring Q?

Me and my mom took out her ring box and we started looking at rings I took out on small silver ring and she told me it was her promise ring. I asked what that is and she told me. I said " the jones brothers have them too " she said those are purity rings. I asked what's the difference and she told me what both mean. What does that mean!!! Does that mean she can talk to me about that stuff and I can have a purity ring?!?! I want to ask her for one, because I really want one! Do you think it is ok for a middle schooler to have one. I 100% know what a purity ring means just saying...... Thx!!!