I used to think I would, but was wavering on it, and then a friend who waited to find out told me she ended up wishing she hadn't, because she had a difficult birth and was way too worried about whether or not her baby was alive to really enjoy the moment she found out it was a girl.
It will be a surprise no matter when we find out, and we're planning to buy/ask for mostly gender-neutral things anyway. I know people will buy some gendered things if they know the sex, but they'll do that after the baby is born, too. And we will absolutely return or exchange gifts we don't need or won't use.
I actually kind of love the way another friend did it - they found out, but had the u/s tech seal it in an envelope and then didn't open it until the shower. We were all able to share that moment with them, and no one knew the sex when shopping. Some people were irritated, but I thought it was great!