Ideas that are are not stated directly but are understood by the audience

I think it means that the writer would desire to leave the city or town Welch as soon as possible, the best time was before he/she finished high school. The Welch was a place preventing him and the other people there from going out to the world. The desire to leave of the writer was so great that he/ she wanted to just leave, despite not knowing the destination and the fact that he/ she could meet a lot of obstacles while leaving.