Legal relationship to birth mom if stepmom adopts me?

I’m 32 and have been having a lot of issues in my relationship with my mom for the past few years. Really, they’re lifelong problems but have come to a head recently as she doesn’t approve of my wife and hasn’t been conducive to me setting boundaries with her.

Meanwhile, my stepmother of 17 years is an angel and we get along great. I’ve been thinking about asking her to adopt me - partly as a gesture to legitimize our bond, and partly to make it easier for me to (eventually) care for her in her old age if my dad passes away, since he’s 15 years older than her.

So my question is… legally, what happens to my relationship with my birth mom if my stepmom adopts me? Does she become “not my mom” anymore? I’d have no desire to tell her I was doing this, and I do want to be able to help her out too when she’s old, plus - more selfishly - I’d like to be able to inherit what she’s planning to leave me as her daughter (I’m an only child and she owns several houses and a good deal of investment wealth). Would my status change in the adoption scenario?