Good job! Would never know you were "new to this"! 😉 To start, beef-up your About page. Make it more personal, tell a story -- do you do Martial Arts, MMA, Boxing? Talk about why you started the store and include some photos of yourself. This would help to personalize/humanize the site to be more than just another eStore.
Not being familiar with your niche, are your prices competitive? That could be a reason why folks are shopping around but not converting. Also, interrogate your "visitors". Are they people or bots? What pages are they gravitating to -- work on those to add more detailed descriptions if possible.
You could also add a FAQ page that has all the questions you get asked most that can help folks make the decision to do business with you.
Consider adding a blog with fitness and training tips. In today's online environment just putting items up for sale really isn't enough -- you have to be a hub of information and as good as -- if not better -- than the sites already online doing what you do.
If you are new, it takes time to get out there (are you working social?) and get noticed. Oh, yeah, change the copyright notice to 2019 at the bottom of the page to show the site is being paid attention to.