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.
While this is definitely a viable option, there is absolutely a strong case that CHA should be your 2nd priority. Firstly a lot of the oath abilities directly benefit from a higher CHA (sacred sword, healing radiance, oathbreaker's 7th level ability). Furthermore the level 6 aura is a passive aura which helps allies in a certain radius, so it's doubly good. Technically your con save will be the same at 6 with a 16 CHA and a 14 CON, the only difference is one less hit point and better all round saves for you and your nearby teammates.
Finally there is an item which is easily obtainable which will add 1 point of CHA at the expense of 1 point of INT, which is a pretty good trade off for a paladin. Under the new stat rules anyone can get 15 CHA at start, so that's a +3 to a very useful ability with a lot of benefit.
Just depends on how you want to play them