Is it Normal to be getting Questions Wrong in the OG 12.

It's completely normal to answer some of the OG questions incorrectly, especially toward the end. The OG problems are organized in terms of difficulty. The easiest problems are in the beginning, while the more difficult ones appear later.

Don't stress yourself over it too much. Treat the OG books as a way to reinforce the concepts learned from the MGMAT guides. And make sure to keep an Error Log. Make a note of every single incorrect answer and determine the reason why your choice was wrong (math error, time, no idea, etc.). And time yourself. If a question takes longer than two minutes to answer, then consider it incorrect. Redo the incorrect questions later.

If the concepts are not sinking yet, reread the MGMAT books. But you are probably strong in some areas and weak in others. That's why the Error Log is so important. It tells you which specific sections that you need to improve. That way, you won't have to read the entire book again.

Without question, scoring above a 700 is not easy. It takes months of proper studying and training. But it can be done. Right now, just don't let your OG experience discourage you. And once you have successfully finished the OG, move on to the GMATClub Tests.