Hello Marie May, welcome!
Yes, many of the problems beginner knitters have wear off with practice.
I have a suggestion though. Count your stitches, and count them after each row for a little while, until you keep getting the number you expect.
Sometimes holes are not dropped stitches, but rather ones that have been accidentally picked up where there should be none! If this is the case, what happened was you either got the yarn caught over the needle (known as a "yarn over" this is sometimes done on purpose to create lace)... or... you didn't get your stitch pulled all the way through the loop so you got a slipped stitch and a yarn over rather than a knit stitch. Both of these create holes, but fortunately, not the kind that run.

Counting your stitches should help. If you wind up with an extra stitch, you can either ask someone to show you how to "unknit" the last row, or how to fix the mistake.
