When to modify for pregnancy?

I’m not 100% sure this is the right place, but I just found out I’m pregnant (not even 4 weeks) and I do a HIIT mom’s workout group several times a week. When do I need to tell my instructors that I’m expecting? My husband wants to wait (won’t get to see Dr until at least 6 weeks and OB not until 8 likely), just not sure when I should cut things out like jump lunges/squats, abs, etc. or if pretty much anything I was doing the last 7 or so months is still fine. Thank you!