Or, just take your girl with you to pick the engagement ring. It's what I did, and she loved it. The whole fucking weekend, visiting jeweler after jeweler. We worked out a budget beforehand, because we're adults, and she tried on about 20 rings before finding one she loved for half the budget price. Win-win situation, cause she got exactly what she wanted, got to be coddled and fawned over by jewelers all weekend, and I didn't max out my budget overthinking the whole damn thing and going in for some big expensive ring.