Just stick at, stay calm, be confident and you'll be fine when it comes to the tests.
Last July I had never been on a bike before, then did Theory, CBT on CG125, 2hr 1-2-1 training, then 3 days of DAS on CBF500. Passed the lot first time and bought myself a lovely Fazer 600 in blue in the September. Been commuting into London every day since - loving it. Never bothered getting my own 125 to practice on, so you've got way more road experience than I had back then, just don't get stuck into any bad habits and I'm sure you'll be fine.