Bulla.
Bulla is the fourth strongest in DB: NGX. She is the daughter of Vegeta and Bulma and Trunks younger sister. She is also gonna have to protect Earth to but she mostly relies on her older brother and the guys. Her best friend is Pan. Her other friends are Goten and Gohan. Bulla and Pan go into the ROSAT for nearly 2 years in total (1 year at a time) and become Super Saiyans.