D5100 LCD unusable for manual shooting...should I care?

Thank you all very much. This will be my first DSLR, and I'm taking a digital photography class in the spring semester. My questions come from ignorance (plus being crazy). Your replies put me at ease.

I waffled around since Thursday over what to buy, and when the D7000s sold out yesterday, I got a D5100. One of the salesmen told me to drop back by this morning, as they might have some D7000s appear in the ordering system which gets dysfunctional during Black Friday. I went by this morning, and they had received one D7000 overnight with the 18-105 and the manager switched the $1500 price back to the Black Friday $999, and I instantly traded the D5100 in on it. I expect to keep it for many years.

I'll have many questions in the future, and I look forward to future threads.

Thank you,

Jim