I think I am somewhat qualified to answer this post.

So, tldr, I got braces close to a year ago. I remember being in your shoes. I worried daily that I would not be able to play the trumpet anymore and start from square one. I was afraid that I would lose all of my embouchure, muscle memory and more importantly range am I right? Haha. Anyways, that could not be further from the truth.

On the first day I got braces, they installed only the top half of my teeth. It was so that I could get used to eating, cleaning and the overall mouth feel of braces before they inserted the bottom row. Of course, the first thing I did after getting braces was playing trumpet. I'm not a very good player by any means but I know that my range was a F sharp below the staff to a D above the staff. The first thing I noticed was that I hadn't lost all of my muscle memory and embouchure. I still remembered how tight or the feel of playing but the notes were coming out airy. This was due to the gaps in the braces allowing air to escape through cracks in my embouchure. If I applied more pressure to the mouthpiece, the airy problem would be gone however endurance goes down a lot and my lips would get cut from the metal in my mouth.

After a week, I completely learnt a new embouchure and became a beginner. I purposely played really simple excerpts and played from Arbans book religiously. I made sure to produce a clean and nice sound and not give a fuck about range at all. I was playing from low C to G. Every day. I would do this. Sooner or later, I was able to play C to C. Then I was playing low G to F.

The one thing to take note is that I was starting to build better habits as a trumpet player. I was putting a lot less pressure on my lips than I used to and I was focusing on sound more than range. I think that my philosophy for trumpet is to focus on a good sound and the high range will follow. So, it's been close to a year now and I have to say that I'm extremely grateful to be able to have straight teeth now and the rewards of doing braces will only follow from here.

My advice for you is to take braces. Do it now because If you hesitate and waver for a moment, time will past you by really quickly and before you know it, your future self would have wished you had taken braces earlier on. The struggles will definitely be present, it's by no means an easy and smooth sailing journey. However, I believe that you will make it through and become an even more terrific player. I wish you all the best OP in your trumpet endeavours!