I usually go early enough to check in and go through security with time to spare just waiting to board in the terminal so I can stretch my legs or get a decent cup of coffee (Delta's coffee is the WORST, don't drink it!). I like the machine check-in if I'm only taking a carry-on but if I'm checking baggage I always go to the people-manned check-in. I've printed out my boarding passes before and I've seen people use the Delta app and have security scan their phones as their boarding pass. I haven't tried it myself though.
So you don't have to wait to go through security, just do it right after checking in.
Have a fun flight!