Four and Tris were dating when he left for dauntless after he got into dauntless for good he came and visited Tris and they had sex and she got pregnant 2 years later with her baby she transferred to Dauntless. (She was only a year younger than four but they let her have her baby before she decided what fraction she goes into.) (She practiced fighting before dauntless)
Warning ⚠️ I wrote this a while ago meaning like 6th grade so the grammar and the flow is dreadful ⚠️