My Bra size....I think

So I was curious of what my bra size would be. I went out and got one of those sewing flexible tape measures. I looked on a few sites and followed what they said to do. I got 2 different sizes, so maybe someone could clarify which one might be right. Now mind you, I'm not the thinnest in the world (working on that, but being realistic). Here those are:

The measurement under the armpit but above the middle of the bust line and then also the middle bust line said, 50B

The measurement under the middle bust line and then the middle bust line said, 46 or 47c

Mind you I have not taken any hormones or creams or anything else that would increase my breast (at least not that I know of).

Also today, I was trying on some clothes my wife had in the back of the closet. The sizes were 16,17 and 18. To my surprise, some of them fit. I noticed that some I would either need to not wear panties or wear a thong. So I may try to wear some of those around when I am home alone.

I have been trying to keep up with my nails. Two more need to regrow a bit more and then I can trim and file them and then they are good.

If anyone has any ideas or knows which way to measure for sure, let me know.