It sounds like your girlfriend is a strong procrastinator like me whereas my wife is more of a planner like you seem to be. Since I've been happily married for a couple of years now it means that it can work.
what is important to you?
What you need to do first is decide for yourself which things would be actual deal breakers for you, and which things you're probably able to live with. Things like driving her around, helping her decide which car to get, helping her make a general planning for the next few weeks to make sure all the important stuff gets done, etc...
The next thing you need to do is find a calm moment and sit her down for an important talk. Make sure you both take the time to do this so that you can both listen to each other and really talk things through. (So don't do this just before bed time, or when you're going some place in an hour).
Start by explaining how her behaviour makes you feel. Make sure to use I statements. This is hard! Especially since you have to try not to blame her. Tell her that you really do love her but are scared that this relationship isn't going to last if you keep feeling the way you do.
Then allow her to explain her side. Ask her how she feels. Make sure not to argue with any of her feelings, no matter how trivial they may seem to you!. Try to really understand what she's feeling and why she's behaving the way she does. Perhaps she's been under a lot of stress lately and her only coping mechanism is to postpone any decissions or hard things despite knowing that it could make things worse in the long run.
Once both of you have explained your feelings try to work together to find a way around the major issues. Perhaps you could make a calander where you put in the important times for major things when she has to do those things. Something like "friday evening januari 24: decide what is important to have in my car", "saturday 25: go to car dealer to find a car", or recurring things like which rooms to clean on each weekend.
My wife has made us a shared calendar with a plan for which rooms to clean and which clothing to wash each weekend. That way we both know which chores are expected to do that weekend but we can decide ourselves at what time to do those. Whenever there are other things planned for the weekend (like birthday parties for example) we can clearly see if there's still time left to postpone a chore, or if it really has to be done right now.
Make sure your girlfriend agrees with the dates you're putting in or if she doesn't, allow her to choose a different time, or even to change the date right then, as long as she always picks a new date when she is going to do it. Show her (mostly with body language, and kind words) that you don't mind helping her plan the important stuff, but that she has to do it.
By having such a plan and knowing things will get done in time it means neither of you is going to (or better, neither is allowed to!) complain about things if they're not expected to be done yet. The only thing you're allowed to do, when she's not starting a job when it's planned at that time, is to ask if she needs help doing that task.
Quick note here: I actually mean a moment when to start doing a chore, not a deadline by which is must be done. The deadline would cause me a lot of stress knowing that I'm going to postpone it up till the last possible moment, whereas the former prevents me from stressing about not starting it yet because I know I don't have to untill that moment. For example: I'm free to play video games saterday morning and my wife is not allowed to complain about not cleaning the house yet because I prefer doing it in the afternoon, or on sunday.
After you had the talk and you've tried to find solutions to your deal-breakers, there will be a moment where you have to decide if she really is the one for you. We can't decide this for you. Try to be really honest with yourself when making the decission on whether or not you want to continue the relationship. Don't expect things to change when they have not changed after talking it through with your girlfriend. If you already know it isn't going to work then it's better to end it sooner rather than later, so that you both can find someone else instead.
All that said, I do expect that it's possible to fix your current relationship. As long as both you and your girlfriend are willing to work on making things better. Try to compensate for each others weaknesses instead of fighting over differences. There is a reason that you've been together all this time right?