The girlfriend will know, and so will her best friend (trust me!), who doesn't care about you guys enough to respect your secrets I'll bet.
PLEASE be careful!

IMHO, you guys are FAR better off to stay tiny, and keep nothing more than the equipment needed to start a few seedlings in February for an outdoor grow in spring.

When you are financially able to get a spot that you and only you have access to/control over, then consider flowering.

2- New Wave T5 fixtures will be perfect to get a couple trays of seedlings off to a healthy start. Finish your share of them outdoors, in separate locations that the other partners aren't aware of.

Blooming plants seem to draw trouble to young growers the way a pile of dung draws every fly in the neighborhood.