Revolutionary idea
Go to club shop
try one on which you think might fit
It it fits, purchase
If it doesn't, go a size up or down to accommodate your original misjudgement, and then purchase.
I can't help thinking if I'm overly sarcastic today, or just surrounded by numpties.
P.S. Shirts are to be worn on the upper body. HTH for those who are confused.
I'm here to help.