It’s a nice gift but a modest one also. If you can afford a better present go for it. A key chain is a nice present and this way she will always have a picture of you with her,but, in my opinion it’s too simple. Try to take her out to a nice restaurant,not too expansive but also not the cheapest.Also try to buy her something that you surely know that she likes.(a teddy bear for example) Also if she likes having fun you can take her to a funfair where you can ride different machines and have fun,maybe even some romantic moments.(this is an even chipper method but more nice in my opinion) If you can afford something more expensive you can rent a plane or a boat and have his way a very romantic moment.I say that if you love her very much you will not look at the money and you will choose the best present. That key chain is not a very bad idea but there are many more ideas that you can use. But I think the idea with the restaurant is the best,this being the most classical birthday present for your half.I also suggest to take dinner at your home,cook something,put some candles,a bottle of champagne and the atmosphere and romanticism are guaranteed.So happy birthday to your girlfriend and i hope that you will choose the best present ,that will make both of you happy.