Or Get off the Pot??

I have been in my current relationship for a little over five years. My girlfriend is almost thirty while I'm twenty three. We see things differently; some times for the good, most times for the bad. I started dating her straight out of high school (I actually met her at my a high school graduation party) and I admit being in a relationship with some one older took some getting used to. There were a lot of people who said it would never work and that we'd be over in a couple of months. Well, five years later, I'm at a cross roads. I've been thinking of proposing fro about two years now, and every time I work up the nerve something stops me. Its either we hit a sour patch in our relationship, or its money, or its just something stupid. Like I stated before, I'm younger than my girlfriend and she has already found her station in life,and has a job she loves, while I'm still working at a dead end retail (Mc)job slaving away just to make enough money to pay my bills. While I am currently searching for more, and even considering going to school, I feel as though she's rushing me to be in the same level she is. I don't think it even phases her that no more than a year ago she was just like me, working a crap job and making no money. She has had time to grow and live her life (and yes she was my first and only, but I was not hers) and most times I hate her for it. I feel like I never got the chance to be free and make stupid mistakes that most guys my age have made, and used those mistakes to grow into a better man. She berates me about how much she does in comparison to me, and how much I need to improve, acting much like a mother instead of a mate. Meanwhile, I'm doing all the house work, yard work, and keeping my own job. I know I'm not a martyr, and I know that she wants me to improve out of love, but I can help but think some times that she is running my life, and I have no control over anything. I uprooted myself from the only home I knew for eighteen years and moved to a new state just to stay with her. I'm ranting at this point, but my question is, has any one been in a relationship like this and how did it work out? Is it time to throw in the towel, or do I need to buck up, be a man, and marry the woman I think I love?