Can I smoke cannabis on my apartment balcony?

Asking for a friend:
Hey everyone, so I go to college in Washington, where its legal to smoke weed if you're 21. I'm not 21 yet but moved into a new apartment that mostly college kids live in. Smoking legal or illegal substance (meaning tobacco, weed, vape, etc) is not permitted indoors or in the stairwells outside. But the lease mentions nothing about porches or balconys, so I assume you are allowed to smoke there if it doesn't say otherwise. My balcony faces a hill going down so there is no street anywhere in front of this side of the building. Since I'm underage, I don't want to smoke weed on my balcony if I will get in trouble. I've only been here a few days, but today I saw two guys smoking out of a bong on their balcony like it was no big deal. Keep in mind mostly college kids live here and there's parties going on that I haven't seen get stopped. Ive been to other apartments in the area where people smoke hella inside and dont get busted, but i just want to make sure im not stupid. Am I safe to assume I can smoke on my balcony like those guys were? Or would a cop come bust me? Or would he assume I'm 21 and legally smoking on my balcony? Thank you!