Would taking heavy armor feat be worth it Frontline Battlesmith at level 4?

Hello everyone I am starting a campaign next week as a Dwarf Battlesmith. I have taken Origin Feat Tough so I get a +3 HP every level up planning on using a Shield + a Battleaxe/Warhammer

Basically trying to be the crazy mad scientist frontline Dwarf. I know I could go armorer and just have heavy armor proficiency but I like the spell list and everything else about the Battlesmith more for what I want the character to do.

We are starting at level 3 so in one level I can choose a feat. Initially my plan was to go War Caster

This would bump my INT to 20 as its currently 19 which I know is huge but I am unsure what would be better early on having the ability to use heavy armor or getting the advantage on con saves and the 20 int

Here is info on my character currently this is 2024 rules 5.5e and 5.5e expanded rules

Race: Dwarf
Feat: Tough

Level: 3
HP: 36
AC: 14 (will be 16 with shield)

STR: 13
DEX: 14
CON: 16
INT: 19
WIS: 15
CHA: 13

Proficiency in: Con, and Int saves. Arcana, Insight, Investigation, Perception checks