When your hair is braided, is it really tight? Tight to the point where you can't move your forehead? If so, that is something to worry about.
Also, when your hair is braided, does the braid styler try to take every single strand of hair on your edges so that you can't see any baby hair? If so, that is a reason to worry.
I had a lady do that to me, and when I first thought my hairline might was receding because of it, it was true. Of course, she said that my hairline was not, but she was not telling the truth.
If you think your hairline is receding, it probably is. I stopped getting my hair braided immediately as soon I suspected it. As a result, my hairline is fine.
I have my hair braided now, but this person specializes in healthy hair braiding. My braided hair is not tight, and she did not take my edges in. Thus leaving my natural hairline in tact. You need to find someone like that.
Its good to give your hair a rest from braids, I did that too.