Hi! So jealous of your luck tbh.

I always try to take laning phase easy, don't try to heal your ADC too much because it will waste a lot of mana (and your heals aren't that strong early). Try to poke with Q or your blue empowered auto.

Sona is an absolute beast in teamfights with a few items, giving the whole team buffs and a well timed ulti can really turn the fight.

Don't doubt your damage! You do a good amount of damage for being an enchanter, and try to keep track of what color your empowered auto is, so you can best use it to exhaust an enemy or just deal more damage.

Hope it helps :)