I'm a 37-year-old male, too, who just got metal braces (just on the top so far) back in June.
I'm married so I haven't been concerned about braces affecting dating, but I have been worried about how other people would react or what they might say. My teeth also looked pretty straight when smiling and talking, but I have a deep bite and a class 2 bite. So I worried that people would tell me I didn't need braces, or would judge me in some way or tease me or something. I also had braces as a kid, so I wondered what my family would say.
So far, though, every reaction as been neutral or positive. Some people, who I'm sure have seen my braces while I've talked, have said absolutely nothing and reacted in no way at all; makes everything feel normal. One person, just this past week, asked when I got braces; I told him June and that was the end of the conversation (I'm surprised more people haven't asked that, or how long I'll have them for). One person said they looked good, and had commented that he wished he had gotten braces. Saw an uncle of mine that I haven't seen in three years, and all he said is he asked "How are the braces?", no no questioning it or any other kinds of comments.
Overall, people are supportive, or really don't care either way and just ignore the braces.
I know it's hard to read this and know this and then actually believe it deep down and not act embarrassed or worried. But other people will not think less of your or react negatively. Still to be seen how people react once I get elastics, or anything that might give me a lisp.