Promise Ring

So I've been with my boyfriend for about 6 months and I'm completely in love with him. We've been best friends for 7 years and we finally got together. For Christmas he's been asking me what I want and what I really want is a promise ring. I'm only 19 and we haven't been together long enough to get married obviously but I just think it would be amazing to have a promise like that. He's kind of oblivious to anything sentimental and I hinted to him that I would like jewlery and that I basically only wear rings but I feel like he didn't get the hint. I'm not going to get my hopes up because he may not be ready for that but I was just wondering if anyone had any advice on how I can't hint to it more without actually saying it.