It honestly depends on the girl. If she loves surprises and grand gestures, go for it. It’s a once-in-a-lifetime type of thing (hopefully), so you want to make it special—something she’ll remember forever.
If you know she’d hate being stuck in the center of a flash mob, or you don't have the time, money, or energy to get Taylor Swift on the phone to make an appearance, there’s nothing wrong with something intimate. Think back on things the two of you like to do together or places you’ve enjoyed going on dates to get some ideas.
Really unexpected is always a big hit, especially if she’s a planner, so try not to drop any hints or raise her suspicions. For example, tell her (numerous times) you don't see the point in getting engaged anytime soon, and later, make plans to celebrate her new job/weight loss/birthday/any excuse you can think of at a nice restaurant and pop the question there.
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