No you can't gain UKARA as you're not over 18.
Your Dad will need to play 3 games in no less than 2 months, as in, there must be a 2 month period between the 1st and 3rd game. He can play as many games as he wants but he won't complete the requirements until the 2 month period is up and a game has been completed after the 2 months is over.
He can then buy guns and gift them to you, as in, a present, you can't pay him.