When our son was 17, I took him to our local bank (Wells Fargo) to open an affiliated Visa credit card, no annual fee, cash rewards, initial limit of $500. He already had a student checking account there, & we had an account & history there as well. DS was primary on the card, I was secondary. He used it primarily for gas purchases & paid it off in full every month, earning some cash refunds in the process. After two years, the bank had raised his credit limit to 1.5K & his credit score was 780, even though he's a full time student working summers. Last spring he was able to get a Capital One Quicksilver card on his own with a $3K limit.
Bottom line: try your bank first for a starter card, start small, never miss a payment.
I wouldn't muddle trying to establish credit with a rollover, which usually costs 3% up front & can be tricky.