I started bow hunting at 15 years old. I started at 35#. I am 45 years old now and hunt at 60#. My advise is to practice practice practice. The strength will come. I would also advise you to hunt at a draw weight that is really easy for you to pull. especially if you hunt in colder weather. It will help you keep movement to a minimum while drawing on a deer and allow you to hold longer if the deer freezes up on you. You will also be more accurate. If you wonder if lower weights kill deer just check out my web site. The proof is there.A well placed arrow beats draw weight every time.
Good luck hunting.