Could you possibly put the file on thingiverse? I would love to print some small ones to hand out at competitions.
I would HIGHLY suggest getting in contact with FIRST directly before posting the files. There is a proper way to deal with the FIRST logo; they’ll probably have some suggestions to assist with doing it right. For FIRST teams, use in a way relating to FIRST activities doesn’t need permission–but posting on thingiverse opens up the logo to anybody to download, and doesn’t necessarily fall under “relating to FIRST activities”.