Will using birth control pills now improve chances of fertility later?

Won't help fertility. If your periods are regular pills won't help you conceive - they're designed to prevent pregnancy! if you have irregular cycles birth control pills regulate your bleeding but don't help you ovulate (release an egg) or help you get pregnant, for example if you have an ovulation disorder like polycystic ovarian syndrome (pcos). If you're ttc at 41 see a reproductive endocrinology and infertility md.
Not really. To be completely honest, at 41 the chance of pregnancy is low to begin with solely based on age related decline in fertility. You should see what your ovarian reserve (egg quantity) is and plan from there.