Materia masters, please help me, I'm about to have a melt down.

[Satcom]

So from day one, I've been dead set on doing my very own armor and weapons, materia and potions, every single thing, I've wanted to be self-sufficient in.

It started with Heavy Iron Armor, I made it, tried to put Vitality 1 into it. It told me the item level was too high and would not be effective. So I said, okay, next time, I'll make the armor closer to the materia and it'll work better.

Second attempt, this time level 32 Steel Scale Armor, and naturally, level 30 Vitality 2 materia. Again, I get a message, this time item is too low, and it is +0. What am I doing wrong? Why can't I put materia in my armor? Why does armor other than the same level as materia even have slots in it, if you can't put anything into it?

Please help me, I'm so irritated right now.

Also like to add that I am level 32 armorer so it should be fine to meld.