Complex sentence: At 18 1/2 he is the oldest member of the gang except Darrel "Darry" Shaynne Curtis, Jr. (Sodapop's older brother) and possibly Dallas Winston and only continues to go to school because he thinks its fun.
Split into simpler sentences: At 18 1/2 he is the oldest member of the gang except Darrel "Darry" Shaynne Curtis, Jr. (Sodapop's older brother) and possibly Dallas Winston. He only continues to go to school because he thinks its fun.