Yes, you most certainly can move any time you choose, but doing so may cost you since there is time left on the lease.
If you choose to leave early try to negotiate the move as best you can with the landlord. You are NOT automatically on the hook for the total amount of rent for the remaining months.
Once you leave the landlord has a duty to re-rent the home as soon as possible in order to minimize the loss. You can help your cause by making sure the home is in excellent condition and ready for a new tenant to move in as soon as you are out, and you can also aid in finding a qualified new tenant. The landlord can charge you the cost of advertising and what-not associated with finding a new tenant.
If the landlord does not make a good faith effort to rent the apartment then you may not be responsible for paying the remainder of the lease. If the landlord does make a legitimate effort but fails to find a new tenant THEN you are responsible for the remainder.
Don't let them con you in to paying the full amount for the remaining time up front.
If you leave early you may have some difficulty getting your deposit back. You may need to go to court in order to get it back. If the landlord does not comply with the rules established for returning your deposit, and if you can show no effort was made to rent the place once you left, then you might have a good argument to get the court to order the landlord to repay you.
That said, if you don't get your deposit back and prefer to call it a lost cause, the only way the landlord can get another dime out of you is if the landlord sues you for unpaid rent- which is when the legitimate effort to rent the apartment will come into play.
The easiest way out is to keep it friendly, INFORM them that you are leaving on a particular date (make sure you still give proper advance notice IN WRITING), and agree in writing to the terms. If you agree to forfeit your deposit as a penalty then that just might be your easiest way out.