from two naps to one

Dominique • Myles John 3/8/16. Micah Robert 6/29/17 baby girl due 10/8/20
When did you lo one go from two naps to one? My son is 11mo and is starting to take a long time to go down for his naps. Was doing 15mins max and now sometimes 30+mins and then only sleeping an hr (was 1.15-1.25) he is also taking st least 30mins to go down at night and waking up earlier then usual in the morning. 
It's been about 4/5 days of this. Should I give it more time or does he sound ready to be moved to one nap?