If you're riding casually you might consider an ebike, It will build you up with assistance, you will be able to enjoy riding more and be less winded. You didn't say what type of bicycle you're riding. Some might say that you're cheating, but you can do what your body tells you that you can do. An ebike my be a great way to get into riding especially hills. I ride both, but the ebike helps you to recover faster and gain confidence. You might just use two or three levels of assist. Think about it.