Rate my first Yugioh deck?

Depends on the people you play with. I don't say this because it is bad, it's just that tournament players are horrifically good. If you're a casual player it's not too bad, i'd say about 7. Pot of Greed is banned from any tournament play. Regardless, it's still a good card. Personally, I'd double up on some of the more important cards, like a third Dragon Mastery or another Dragon's Ravine, rather than Horn of the Unicorn. It screws you over sometimes. But i'd say about 7 or 8.