I propose that this woman who's being fantastically created in our imaginations is not real. Oh sure, she's something to strive for, and don't get me wrong, I will damn well make sure I'm balancing it all at some point, but if you're picking "this woman" who you should be, you may just lose sight of who you are.
Yes, the first step in any self-help regimen is identifying who you are. And once you do, you're supposed to be able to "fix" whatever is wrong with that you - the you who can never find the time, doesn't make enough money, is just disappointing - and move on from that you, the you who you were before you decided you were unhappy. There is validity in wanting to change to better your life, and I'm in the process of doing so myself right now. But the other day, I was in the car and an older punk rock song (or really, punk rock opera of sorts - NOFX's The Decline) got me pumped up. I found myself missing those 16 year old Doc Martens and the cursing of the establishment, that soul searing satisfaction you feel when you're sure someone else is to blame for all of the world's problems, and realized that I don't have to be nostalgic for that person. I don't have to lose that person because she doesn't fit the picture of what the gurus and society as a whole expect me to be as a professional woman, a mom, a wife, a human. I can still have me and change for the better. I just have to change that which I actually want to change, not that which I think others might want me to change.
In my rambling here, I'm trying to say that you should, absolutely, envision your future. Identify what you want to do that you're not doing already and do it. But don't forget who you are - not who you were. You can leave parts of yourself that no longer serve you on the road behind the truck, but that which makes you feel, that should hang out somewhere near you, maybe in a box, a trunk, a bag, until you decide it's a great car ride home to listen to some punk rock and take it out again.