I used to knit a lot in the past (moderate talent … at least back then) … I am trying now to use a pattern I have done a million times for a baby but, since it’s been so long, I am having trouble. I pulled out some yarn which I had used in the past for this pattern and ordered (hopefully) enough of each color to create another masterpiece! 
The pattern calls for size 3 and 5 needles. The gauge on the pattern reads 4.5 sts = 1". I have started this 2x and it just seems too incredibly small! The band around the yarn (Berroco Comfort) and it’s gauge reads 4.5 sts = 1" (for #9 (18 sts)) or 5 sts - 1" (for 8" (20 sts)).
Would someone be able to help me figure out what needles I actually will need to use to make this sweater? (So much more older, but no more wiser…)
Thank you, in advance!