When he was 12, he nearly stood up for a friend, Billy Stockhausen, who was being bullied, but did not, and has hated himself for it ever since. In 1954, he tried reading How to Win Friends and Influence People, but the advice he gained from this book made people stay away from him even more.
George was probably bullied from a very early age, not just by Biff but by other classmates such as Mark Dixon. He had been attracted to Lorraine for some time by 1955 (they may have met for the first time upon entering high school) but was too scared to ask her out.
In the original timeline, George and Lorraine fell in love when Lorraine's father Sam knocked George over in his car due to George falling out of a tree into the road (he had been "birdwatching", watching Lorraine get undressed from the tree). The Baines family took George into the house and Lorraine felt sorry for him. In a "Florence Nightingale" effect, she fell in love with him and they had their first date a week later, at the Enchantment Under the Sea dance. George had been considering college but waited until the deadline to decide whether or not to send in the application. He knew his father would talk him out of it, so he likely gave up.