Exactly what I have experienced. Even whatever time is mentioned in the cookbooks, I was never able to beat it. It takes a minimum of 45 minutes to prepare a decent dish for me. I too am an amateur and I measure my time with my mother's time and I see a difference but not so much. I do not do multitasking if I have something on the stove which requires constant stirring or moving around.

Also I found that slow cooking brings out the best flavours and aroma.