Darker period blood as I age = progesterone problem?

Sarah • Married to the love of my life 11/18/2018 👰🤵 | Brenwyn Elizabeth born 08/27/2020 👧| Cookie Monster due 12/19/2023 🤰

I’m 37, and my new husband and I are TTC within the next few months. Aside from my age, I’m healthy and don’t have any obvious infertility issues. However, I’ve noticed that since I was about 34-35, my periods have included more brown and dark red blood than they used to. I’m definitely going to discuss this with my OB/GYN at our upcoming appointment, but in the meantime I’ve been researching the issue online (not the best idea, I know). I’ve read everything from “that’s perfectly normal; your uterus is just expelling old blood” to “MENOPAUSE ALERT” to “have you talked to your doctor about low progesterone?” Have any of you ladies had this issue and discussed it with your doctors while TTC? If so, any results or insights you’d be willing to share? I’m not about to blindly believe whatever I read online, so I’m thinking that listening to other women’s experiences, and, ultimately, my doctors’ advice will help me understand what’s going on with my body.