When does goten reach ss1?
During his training with Chi-chi, Goten went super saiyan. Chi-chi scolded him for it and told him to never transform again. That marks the point when Chi-chi obviously has something against super saiyans. Goten didnt have to get angry to become Super saiyan like Goku and Gohan did. When Gohan saw Goten go ssj, he was shocked to see he was able to do it so easily. Trunks also was able to get his ssj powers without really trying.