The problem with all of the other answers is that they are evaluating late-game characters as early-game. Someone said, "Plate armor is 1500" - At level 1. do you have that?
Dropping your highest stat in Dex, Con and Cha while taking a race that has a bonus to either one (Dwarves) of those stats, two (Tiefling variants) or all of them (Human/half-elf)sets you up nice.
Str Paladins have to play catch up in the beginning on Armor and sure they can out damage you. But that isn't as important as survival period and to start Str Paladins get Chain mail which is AC 16. A fair Dm will let you exchange starting equipment for Chainmail for Scale mail. Or studded leather if you have +4 or +5 by rolling 17 or 18 for Dex then add in your race bonus.
It really doesn't matter if they don't allow you to the low level enemies will have this armor on them. Take it and simply sell your Chain mail for 35g. Take a shield as part of your starter equipment. At this point the Str paladin has to have a shield to be be one AC point behind you at worst if your Dex is a 14 or 15 with races bonuses.
They're saving to buy plate a Dex Paladin is saving for a +1 Studded leather or Adamantine Medium armor. Which is a lot lower than a +1/adamantine Heavy armor even if it's a Breastplate 400gp + 500gp for adamantine AC16 armor with Dex do disadvantage.
If you want an extra point and don't care about the Disadvantage to stealth half plate is 750gp + 500gp either way you have higher AC and can't be hit with Crits.
A Str paladin can't do this unless they rolled very well for starting stats or waste their racial bonus leaving them weaker in other areas.
If you're dealing with a DM that won't let you buy low level +1 items or Adamantine when you get the gold (talk about it in your Session 0) then drop a thirteen 13 in strength. That way if +2/+3 Heavy armor drops no one can argue that you don't need it if you do.
You're already ahead of a Str paladin defensively who has to have Dex for skills they want to use, initiative, bows and Medium Armor or not use those things well. Dividing their decent ability modifier rolls of at least a 14/15 that would be better placed in Cha, Con, Wis or even Int if multiclassing for them.
So unless the DM favors a Str paladin by drops, you'll be sitting pretty. I had a level 4 Dex Paladin hit AC 21 with two +1 drops (ring and Armor) in a Phandalin campaign. And a Crafted +1 Shield (Other guy had Armor made from a Dragon).
This left me with +4 Dex (rolled a 16 +1 Race bonus), +1 scale mail, +1 ring of Protection and a +1 Shield. AC 21 I get hit on crits only but our Fighter instead of getting a armor item got weapons both 2h and 1h for when he wants to use a shield. He NEVER uses a shield only two handed and he rips it up far more than I could which is typical.
With the exception of a couple Oaths the Party isn't relying on you the Paladin as a main Damage dealing. Not with Rogues, Fighters, Casters and etc. But Compelled Duel ALWAYS comes in handy so having high AC will always come in handy!
To me the pally works better as a Tank spot healer than a damage dealer of doom except for those couple of Oaths. That said I did take Dueling as a fighting stance over the plus one AC, I regretted it a few times but I know I need some balance.
Adding feats makes it sweeter:
Shield Master- Bonus action shield shove with your shield. Add Shield Ac to Dex saving throw against spells or other harmful effect that effect targets only you. If subjected to an effect that allows you to make a Dex saving throw to take only half damage you can use your reaction to take no damage.
Good feats for any paladin or melee types:
With a defensive build and Defensive Duelist, you pretty much only get hit by save spells and when the GM wants to hit you. Good weapon upgrades will provide you with damage increases as you level up something should be available.