I'm in a similar situation, I do a ride every Sunday, I started in February, first time on a bike in a very long time, it's 14.8 km all up kill clime is 581 m over that distance, first time I'd did it it took me 2h 25min going up and 37 min going down, I stopped often and pushed a lot.... today I did 1h 47min up and 30min down... I stil can't get all the way without pushing a little ( found out my lowest gear on the back is a 26T.. which I think is way to high for me )..

Keep it up. We can only keep going and build up stamina..have fun.