You've got to give yourself a little slack here. You just started knitting. You can't expect to be perfect right out of the starting gate. It takes practice. I'd say work on the scarf and enjoy it. Get the mechanics down first. Practice so that the movements become natural for you.
What color is your scarf? Dark colors are harder to work with, even with the best lighting. I try not to knit with dark colors at night, only in daytime hours.
As to the correct needle size and yarn...this is way simplified. If you use larger needles and thinner yarn, your work will be thin and holey. If you're making a hat or mittens, it won't keep you warm. If you use a needle that's too small for the yarn, like you are now with the worsted weight, it's a pain to do. You'll be squeezing that needle into the stitches and straining to do it. It's not fun.
Another thing is that it's going to take forever. We knitters want instant results. Large needles somehow help us to get the creation fix we need faster. It's not a big deal with a scarf because gauge isn't important. I usually don't do patterns. I'll measure, gauge, pick the right needles and yarn, and design my own pattern. But I've been doing that for a while now. I saw this pattern that I am in love with and had to do. Almost finished with it now. But I'm using a sport weight yarn and needles that are in the 4 mm range that you're doing now. It's so putzy that I want to scream. But the project will be worth it when it's done. Here's the pattern. You guys might like this. It's a fitted watch cap. This is a vintage WW2 Red Cross pattern. Ignore the number 5 needle size listed here. They must have done sizing differently then. It's a 4 mm which is like our #6. The link is within this article.