Periods of bap training years?

Yong Guk - Started/became a trainee in his 3rd year of middle school

Himchan - Himchan was a trainee nearly for 2 years

Daehyun - was a trainee for a total of 2 years and trained with the group for about 7 months

Youngjae - Became a trainee during song ji eun's solo promoting of 'Going Crazy' (was also a JYP trainee for a year)

Jongup - Was a trainee for 1 and a Half years

Zelo - Was a trainee for a year ( Only in TS, he had also trained for 5 years elsewhere)

--Source