@Jerkica (OP)
Getting to level 6 should be doable if you've done all of the quests on an evil playthrough and level 7 if you did them all on a good playthrough. That includes the Underdark and Grymforge, the Hag, Zhentarim hideout etc. Fighting will get you more xp in many cases than talking as well.
If you head into the Monastery in Act 2 and are level 5 the Githyanki will be very tough, especially the Inquisitor. It's ideal to be at 'least' 6 in that fight.
Caveat: Everything I say above is based on a Tactician playthrough. At lower difficulties, 5 might be much more viable.
