First of all, well done on starting you well-being journey!
Secondly, I don’t believe there are any science based evidence that waist trainers work. Sure they might alter the apparence of your body, but this is just a temporary solution and not a permanent one. If you feel insecure about the way you look and you feel that a waist trainer would help your confidence on a day to day basis then it might be wort giving it a go, but my understanding is that when you don’t use them/stop using them your body goes back to what it was. before.
I would advise you to keep training, get stronger, have a look if there could be any improvements in your diet, and aim for health in the long run rather than taking short cuts. And don’t forget to celebrate your journey and have tonnes of fun in the meantime!