I started with 1941 as well. I really believe the only way to achieve a 90-120 min game is with bad dice / poor strategies. Truly understanding the map, movement rules, and turn sequence is overwhelming. I believe my 1st game was over 10 hours. stretched over multiple days with monumental mistakes by both players.
I have since moved on from 1941 to 1942 2nd Ed and 1940 Europe (almost ready for 1940 Pacific then Global!) I use 1941 to teach anyone that may be interested. I warn everyone in advance to set aside a good chunk of the day. We make an event out of it. Food, drinks, etc…
To answer your question, you are most likely making mistakes. We all did it when we first learned. Hell, I still make mistakes. I’ve lost the japan capital by accident and the West Coast of the USA just by not paying attention! But, i’ve also never completed a game in under 2 hours ever.