Stat priority for a 2h paladin should be STR, CON, then CHA, since you'll be hit more often without a shield. And supposedly there's an item that bumps your CHA to 17 no matter what your original score is, though you won't get it until around the beginning of Act 2. So don't feel bad keeping CHA low-ish for awhile.
Also, bear in mind that by the time you hit 8th level and take Sentinel, you'll be 2/3 done with the game. Your build should be fine until then, but with no way to get a feat on character creation you're going to have to wait awhile before the polearm/sentinel combo can shine if you take polearm mastery first.
Also, unless Larian changes pike mechanics a lot, they don't work with the polearm mastery feat.
