Working full time while doing part time modeling/acting

I just got promoted to a new job along with getting signed with an agency, where this job is more flexible compared to my previous role however I am "on call" if anyone I'm supervising needs anything. I know they say that agents understand we work full time jobs and I want to show up and give priority for both works (like using PTO, working with flexible schedule, etc). I guess I need some reassurance or advice on what this means if I have to turn down a gig due to late notice, especially since usually I can't put PTO in unless it's two weeks ahead of time (although I need to double check on this). Both opportunities came down at the same time and it feels exciting yet so overwhelming. Any thoughts from those that work a typical full time job and juggling this at the same time?