I would throw in one caveat - at least consider delaying launch until your youngest is in kindergarten. You probably won’t be fifty, it’s not that long. Certainly do some legwork ahead of time, but in my experience the earliest years have the least wiggle room. I seriously burned myself out trying like hell to do it all, and in retrospect wish I’d have paused several ambitions for just a few years. In so doing, I’d have been fresh & ready the moment wiggle room returned.