Garter stitch - fixing loose first stitch?

I just watched the video for a complete project which explains how to fix the loose first stitch in garter stitch by slipping it onto the needle instead of knitting it. Can I start doing this even though I am 1/4 way through my project? Will it look different if I start using this trick now? Thanks for your help!

Yes it does look different. What you can do instead is knit the first stitch, give the yarn a gentle tug, and knit the next couple stitches just a bit tighter. That should help after a few more rows.

A loose first stitch is very normal especially when you are learning to knit. The more you practice the better your tension is so my suggestion is to just keep on knitting. That loose stitch usually works itself out, but if you want you can knit that first one and slip the others if you are inclined.

The first stitch is supposed to be loose when you’re at the beginning of a row. Just tug on it before you knit it to tighten it up. I do that anytime I feel that a stitch is loose. Beginning middle or at the end of a row.

Thank you for your help!