I say go for it! It's just a ring. It isn't marriage. My partner bought me my first ring during our first year. We don't really call it a "promise ring" because we both find that a little too cliche and I mean what's the ring promising? That it will never leave or hurt you? To us, it's a mark in our journey together and I feel that "mark" is much more sentimental than a promise ring everybody gets. Anyways, if you love and care for her and truly want to give her a ring there's no reason you shouldn't. I think it's an extremely sentimental gesture and a reminder or "mark" of y'all's journey together. I like that when I glance at mine it reminds me of all things we've accomplished together. It reminds me of our efforts. I say you casually take her to a jewelry store just to get an idea of her likes and dislikes and just one curious trip will give you both an idea of what you want and you'lll be able to tell whether or not she wants to make a next step. My partner took me to Jared and several other stores just to see what all there was to choose from and later he went and bought it. It is certainly a time I'll never forget. You could try that. Just take her in a place or two and then you'll find it easier to make up your mind and you may decide to wait, but if you're already considering it you might just go ahead and do it.