Possibly becoming a HCA!! Help?

i have looked into HCA as i want to be a childrens nurse bt its higly competative this year so if i dont get in im setting up a back up plan. As i was sayin ive been researching HCA and i thought u had to do an apprenticeship first to become one bt someone has suggested u dont u just do training with the hospital ur based at. Can anyone clear this up for me? Thanks