This is an important decision, Seesaw. Here are my initial, yet very brief, thoughts.

Have you considered talking to the current PhD students (and the alumni) of the program to which you will be applying? This can help you have a understanding of the program's demands, expectations, etc. This may also help you figure out the financial aspects as well (should you want to earn extra income while pursuing your studies). Meaning, will you need to earn extra income or will the financial aid be adequate for you to live alone and care for your other financial needs?

Also, there are people who are having children while studying their PhD. It seems doable but again everyone has different limitations and support system. I guess this is something to be addressed when you actually meet someone and decide to have children. We cannot speculate now, because we don't know what is waiting around the corner as far as your personal life.

I guess what I am trying to say is the following: if you can figure out the financial aspect of it, then go for it. The reason why I am mentioning this is because it is much harder to live on a strict budget once you are older (and you already know that) and being a student usually limits once's ability to earn money.

I think academia is a wonderful platform and since i am a huge nerd, I do understand (and identify) your desire to go back to learning and research. I sincerely hope you can find a way to achieve this goal. You know where to find me, should you need to brain storm more.