I greatly prefer mix-and-match ability and skill, this is also how 13th Age does it, but I unfortunately never get to use this rule. In my group I have a few players who exclusively use apps to make their character, and it just stops play and takes a couple of times explaining to get them to understand THIS ability score modifier, plus your PROFICIENCY if you are proficient int THAT skill. No, don't add that skill modifier to the ability, it already has a different ability modifier baked in. Your proficiency. No, I don't know where that is on your character sheet. Look, you're 7th level, it's the same for everyone. Okay, so as your as you are proficient in the skill, you can add that to this other ability. Just roll like normal.