Problem with maintaining momentum/board stopping within a few seconds (3-5 seconds)

Got my skateboard like 4 days ago and I have been learning the basics. I’ve figured out how to balance and can push while keeping my weight on my front foot, but whenever I put my back foot on the board and twist my front foot to the riding position, my board almost immediately stops/slows down significantly. I’m wondering how I could fix that or if it is a problem with truck tightness or something. My bearings are Spitfire Cheapshots, the wheels are Bones 99a, 54mm and I have independent trucks that are pretty tight but I can turn comfortably. The ground I ride on is asphalt, not the smoothest but not that rough. I’m confused because the board seems to have decent ride time when I keep my pushing foot off the board and my front foot facing forward, but stops when I get into my riding position.