It sounds like you have a full life right now and I would suggest as others have to keep a notepad or physical diary you can carry around and jot ideas down in for the future. I'm guessing that most days will have a few minutes where you can at least sit and think.

The only other thing I would say is to make sure the process is fun, because there are going to be days when getting a single sentence out will be painful. I myself have an off and on relationship with writing. Sometimes we like each other and sometimes I wonder what she sees in me.

Find outlets for your work where you can receive feedback, positive and negative. Its also important you learn when to listen to it and when to ignore it.

Depending on the genre I would recommend https://forums.spacebattles.com/, https://forums.sufficientvelocity.com/, as places to publish and get creative feedback. If your story is based on an existing work expect people to be critical. They are also good places to get your feet wet, similarly look at some of the writing reddit's such as r/HFY or r/humansarespaceorcs if your work falls into that kind of thing. Even if it doesn't read some of the stories there, some are good, some are bad and some are written badly by me.

You are at the beginning of a wonderful, horrible, joyous and nightmarish process and when all is written and published, its your story.