Never, EVER, training wheels. She'll 'get' the pedaling. The balance is sorted, she'll never need the trainers. It would be going backwards.
Find a really gentle slope to get her started on. Show her the pedaling and let her rip. We did this with our boys, tho they'd never had the balance bike part, just straight in on the pedals. Boy2 was a whizz on the scooter at 2, and progressed to a bike before he'd even turned 3. Number 1 was 3 when he started on the bike