I'm currently playing a level 3 Aasimar Barbarian.
I'm not sure whether I want to take the Great Weapon Master feat (-5/+10, when you reduce a creature to 0 HP you can make another attack as a bonus action) or to increase my ability scores. I'm a Path of the Lion Barbarian - taken from here
My party is actively trying to help me achieve the 5 ft advantage roll(I assume that's important).
The DM had me roll ability scores, and I rolled very averagely. I would usually be content with average rolls, but I have an underwhelming strength (for a barbarian) of 14, and a constitution score of 12.
From my story, I have a magical Greatsword that was a gift from my background, and it does 2d6+2d4 damage right now. It scales with level, so it's 2d6+1d4 at level 1, +2d4 at level 3, +3d4 at level 7, +4d4 at level 15, +5d4 at level 20.
Also from my background, I wear a half-plate, allowing my AC to bump up to 15, which I'm pretty happy with right now.
Current Ability Scores: STR 14; DEX 10; CON 12; INT 9; WIS 9; CHA 11
I'm not sure what else is relevant, but I've been rolling pretty well on my HP level-ups, so I have 34 HP right now.
TL;DR: I'm leveling up to level 4 soon, and I'm not sure how I should "progress" my character with the ASI at 4th level: with a feat or through ability score boosts?