When I went back to work with my first, my MIL would take her for a few hours here and there so my husband and I could go on dates. That was roughly February and she's a November baby. It's really whatever you feel comfortable with at this point.
I’ve had a bunch of babysitters for my 5mo. At this age it’s very easy to take care of them and so I don’t worry as long as I trust the person.
I let my friends watch him for the first time during a night we were all ganing out and they said go take anap, I felt bad leaving my little (ball of potential screaming craziness) angel for them to watch but the nap was so nice. These are friends I trust no problem but if you want to just stay in the same house and take some "me-time" the first time it'll put your mind at ease and give your friend the opportunity to figure out how to handle hiccups with you there as a safety net
Also we left my baby with dads mom for the first time at like 1 or 2 months to go to the movies
You gotta do it eventually. Try a close or at home date night. A friend could take them in another part of the house for extended time to trial it out.