Reading this and a couple of other posts you made on this subject Fras I'm starting to realize that you will probably let her go. You need more experience, education wise, work wise and relationship wise and these things require a higher degree of freedom. Staying in this relationship will probably leave you feeling like you are stagnating and you probably won't be able to conquer that feeling completely until you get to taste that freedom completely.
Though, freedom is a double edge sword. After a while you will realize it's not all it's cracked up to be and what once seemed like a cool refreshing change can easily turn into an empty and bitter loneliness. Missing her year after year and wondering what it could have been like will probably be a lot harder than letting her go. It's a hard decision to make with heavy casualties on either side of the fence. I hope you will make the one which is best suited for you.
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~