How to choose your hairstyle?

I based on it on a few things. My hair is thick and long and being that we got married in July (turned out to be the hottest day of the year) I was very hesitant to wear it down because I didn't want to be a sweaty miserable mess. My hair also doesn't hold a curl so that also limited what styles could be done. If your dress has an intricate or unique back then I could see not wanting to wear your hair done because it wouldn't show off the back as well.

The hairstyle may partly be affected by the style of wedding you plan-- so the choice can be tied with the venue. Much of the choice can be based on the style of dress and neckline. A good hairstylist could make recommendations based on those factors plus getting the best balanced look for your face and your hair type. You may seek to do a trial for makeup and hairstyle, especially when having a more artistic makeup artist. Of course the choice also depends on whether you want a veil and/or tiara, for example. Check out different looks and get a sense on your own what you like.

One thing you can do is try on something that has the same neckline as the wedding dress. Put your hair in different styles to see what you generally would like. If you have a round face, it may work better to have an updo. Experiment a bit.

Also, you don't have to get overly focused on it. Lots of different styles should turn out nice.

You can have different hairstyles for ceremony and reception. I've seen brides wear a classic low bun or a side braid bun, then take it down naturally for the reception.

I usually consider both - the outfit and what looks good on me. From what you're describing, I would vote for having your hair up. I'm guessing the makeup and the whole package will make you look less like a teenager. Although, I don't see it as a bad thing, to be honest