I never intended for that to happen. I'd been trying to build a family since my first marriage at age 23, but was thwarted by everything from my ex to the Gods of the Universe.
I always knew I would not let anything stand in my way of becoming a mother if I could help it, but that doesn't mean I'm happy about being such an old mother. My DH is 10 years older than me, so that's an additional problem that makes me uncomfortable. I do think there is a "too late" but I'm not willing to draw that line for someone else since I don't want anyone to do it to me.
Yes, you are being influenced by cultural values but also by reasonable considerations. Natural fertility can and does extend to the mid 50's for some women (and is more common in certain cultures). We know that a gene has been isolated by an Israeli RE that explains why some women have late fertility (meaning, they can spontaneously conceive AND deliver healthy babies into their 50's). To my way of thinking, if it COULD happen naturally at a later age, then I don't see why I can't help it along with interventions.
I cannot reiterate Maggie's advice enough. In fact, I'm going to put it into capital letters: GET YOURSELF IN GOOD PHYSICAL CONDITION, NOW!!! I was totally thrown with my twins. They are so physically demanding and I got severe tendonitis in my shoulder and elbows THREE TIMES in their first year of life. Now I'm too busy and sleep deprived to exercise so it will have to wait until they go to preschool. The best advice I can give older mothers is to get in shape (fathers too - thankfully my DH is a hobbyist farmer so is in excellent physical shape from all the work he does). Having said that, I do get very annoyed with critics of older parents who say things like "how's a 50 yr old father going to play ball with his son?" as if all 20 year old fathers play ball with their sons! As if that were the most critical element of parenting! I am not talking about playing, though that's important in its own way - I'm talking about being able to carry out daily chores and functions. I thought I was in reasonably good shape, have no help problems whatsoever except some familial arthritis which I usually can just ignore - but I should have strapped a 60 lb pack to my arms and gone about my daily business. That would have shown me the error of my thinking.
There are many, many advantages to being an older parent. Older parents are much more willing to self-sacrifice for their children, to spend time with them, to spend resources on them, etc.
Lastly, and this is the most important, we had a beloved poster here who no longer posts but she said something once that is my most favorite sentiment ever - she said some people reach age 50 feeling that the best of their life is behind them and they are just waiting another 50 years to die, but that's not the way she sees life - the best is yet to come. Bingo! You will likely live at least another 35 years. Do you want to spend 35 years feeling the grief of being childless? I didn't think so!