If this is happening to anyone else, please say, so after about 1 hour (i suck at this game), i finally got my first Mythril ingot, and i go to make a dagger, and it turns to a small copper blade, please help...

I made a little video on this:

it is being worked on/will be fixed soon: https://trello.com/c/91rjPV85/111-wrong-craft

I'll try to replicate that, if it works, then it's definitely a bug.