Preserving a sense of self/identity

A thought I can't let go of -- and I think is common among at least some fencesitters -- is that I don't want to lose my sense of self. Parents -- especially those that give birth -- become so absorbed in the needs of their kid(s) that they no longer have any life or identity that is separate from caring for their offspring. My mom is like this, even now with grown kids. I really don't want to be.

This is not merely a matter of circumstance. There have been scientific studies, and books, in the last few years showing that the brain chemistry of mothers changes so profoundly after giving birth that it is like a brand new stage of development, like adolescence. If you give birth, your brain sends forth chemical messengers that tell you to focus your attention and caring on your offspring. It does change you, profoundly.

I've worked so hard in adulthood to come to a point where I like myself and my life. It's really hard to give that up. For context, I am over 38 so it took me a long time to get here, and I don't have many fertile years left.

Do others feel the same? And do any birthing parents out there feel like they've been able to preserve their "old selves" to some extent?