Hello,
AFAIK .bash_profile (if exists) gets executed right after /etc/profile, so right before logged in (showing prompt or GUI). The order is:
/etc/profile
~/.bash_profile (if exists)
~/.bash_login (if .bash_profile doesn't exist)
./.profile (if none of the other .bash files exist)
./.bashrc (for none-interactive when already logged in)
So, in my opinion it should be good to put it in .bash_profile. I, for example on my laptop have my .bash_profile that holds some commands and they get executed before my login prompt or GUI (depending which console I log in to).
This site explains a bit more, and more useful, tells you how you can test it for yourself.
Kind regards,
Eric