Sometimes I can't wait till the fall, and with it my classes will come (that means, I hope, I`ll have no time to think of you).

Sometimes I can't wait till the fall, and with it my classes will come (that means I`m going, I hope, to be too short of time to think of you).

Sometimes I can't wait till the fall, and with it my classes will come (and it means, I hope, I`ll be too short of time to think of you).

Sometimes I can't wait till autumn comes and my studies with it (which means that, I hope, I won't have time to think of you).