Adult piano study is different from childhood lessons. The hands learn slower, the ears learn faster, and the most progress happens in the first three years if practice is consistent. Inconsistent practice produces years of stagnation.
Where to start
Slow practice matters. The hands learn what they repeat. Practising a passage at performance tempo with mistakes engrains the mistakes. Slow with metronome, gradually speed up.
What matters most
Start with method-book repertoire, not "real" pieces. Faber Adult Piano Adventures or Alfred adult course will progress you faster than fumbling at Chopin for a year.
What to skip
Play every day, for short periods. Twenty minutes daily beats two hours every other day. The motor skills consolidate during sleep; daily practice gives them more chances to do so.