Shouldn't that be 15 AC? Hide 3, Dex 1, Class bonus 1 = 15.
Means you only need a 14 to stay even with the chain guy (you WILL fall behind slowly since you're not advancing dex; if you compare to say a wizard in leather who gets +1 INTMOD at 8, 14, 21 (x2 if demigod), 28, that's 4 advancements and you're only getting 3, not to mention you effectively start 1 behind if you're only going 14 dex...
I also suspect that by the time you do fall behind you can do some retraining and pick up chain and scale and scale spec and not worry about speed anymore.
Dex 14 also means you just have to find one extra point somewhere to get heavy blade mastery if you go for a fullblade (possibly more interesting for thaneborn, since rageblood is begging for axes/hammers).