What level do you have to be to get the X-01 power armor from the guarded area. I am level 19 and went there and only got bad stuff. I saved before going there first though so it's all good.

Are you talking about the where you go up an elevator to the top of a building in eastern downtown Boston with just the Sentry Bot and Assaultron? Might be possible to do it at level 19. Go up the ramp to trigger the alarm and run back to the elevator so only the Assaultron can follow. The Sentry Bot will stay on the roof and not able to attack until you are good and ready for it.

It is possible that the X-01 only spawns at a certain level so if you are too low, then you might acquire different power armor. So you might need to be level 30 to get X-01 Power Armor from that location.

LEvel 28+ is where it starts having the ability to spawn, BUT it is not 100% going to spawn. I am level 45 and still have found a t-51 and t-45.