If you are taking lessons from a qualified professional teacher, you need to practice the grip he gave you, and use it until you get used to it. That is the answer you will get about 99% of the time on this and any other forum from anyone who has played for any length of time. If you can't hit the ball using a proper grip, something else is wrong with your swing. If you hit the ball with the grip in your picture, you are making compensations somewhere else in your swing. If you swing the club properly with that grip, you will hit low hooks. Learning to hit the ball and learning to score with that grip will hinder your long term development because you will develop a very unorthodox swing to compensate.
There are persons for whom an overly strong, 10 finger grip would be appropriate, but most of them are under 12, over 80, or have a physically limiting condition such as arthritis or some other physical impairment.
As others have said, understand the mechanics of the grip your instructor is teaching, and hit balls with a 7 or 8 iron until you are comfortable with it. It is infinitely easier to do that now at this early stage, than to try to correct after several years the compensations your pictured grip will cause.
No one is trying to be rude or beat you over the head or be overly critical, but a lot of people have been there, done that with unorthodox methods. You don't need to re-invent the wheel, just learn to drive. Sure, through the ages there have been a few funky swings that worked, but 99 out of 100 of us are better off learning sound fundamentals and staying with those.