You're putting a whole lot of focus into your website theme and minor things like colors. Focus first on your products. Titles, descriptions first. Find best pictures from all available suppliers and put them up. Install heatmap. Run tests. If you don't have any remotely profitable products, there is no point in making a really nice website. Your current one could use some work if you are targeting women, but spend just a day or two modifying existing elements that are easy to modify - e.g. change the color of the CTAs to pink. Don't go all in until you know you can be somewhat profitable IMO. If your products are good, website design is secondary.
As for actually editing the website, you should be able to do most of the editing in the theme customization options on Shopify. Go to your theme page and hit Customize and look around.