After 35+ years on an upright it took me:
2 laps around the dealers parking lot to be not-wobbly.
2 weeks, 150 miles to be pretty confident starting, stopping and using clipless pedals.
2 months to feel like I could/should do group rides.
About 1 year, 3000 miles to be as confident doing fast corners, tight group rides and averaging the same speeds as I used to on an upright.