I think squad rank plays a *huge* part in the match making. My squad has no level 10s. For a while, we had a couple who normally didn't war. Our matchups were doable, but we usually faced anywhere from 2-6 level 10's. However, the squads themselves were not great, and we usually had a higher medal count than the opponent (in some cases, I had a higher medal count than the entire war squad as a level 8).
Once we hit rank 40 as a squad, our matchups became nuts. We've faced as many as 13 level 10's, and have had wars where every single opponent's base had a higher base score than any of ours, while the average base score of the opponent was something like 67% greater than ours. We're also getting out-medaled, and at times by a lot. Pretty much every matchup since we hit 40 has been massively lopsided. At most, we've had two fresh level 9's in our wars squads, then 5-6 8's, the same number of 7's, and bases as low as level 3.
Long story short, I think that squad rank plays a big part in the matchups. I don't think rank 19 is that big of a deal. You may have just gotten unlucky (it happens). But when you hit 40, they throw you into the deep end, and we have had almost no chance in wars.