I am looking to build an e-commerce website and have it ready within a month or so. The website is nothing complicated, it is a bunch of products that will be sorted by category and provide online check out. I actually have already started and almost finished it, but I'm using drupal 7 and Ubercart. It is my first time building a drupal site and was following a tutorial, then I noticed how outdated the stuff I'm using are. Would you recommend starting fresh with a drupal 8 core and using the commerce module? I've seen many benefits to this, but I'm not entirely sure it's worth it, since commerce module on drupal 8 is still in beta and payment gateways such as stripe which I'm looking to use, and I believe many more useful ones aren't developed for drupal 8 yet. Any advice would be appreciated. Thank you!
Your questions is opinion based and it will probably be closed because of that, but I'll give you my (opinion based) answer anyway.
If you want to develop e-commerce site fast and you don't need too much customization then Ubercart is probably best solution Drupal world can offer you. Drupal commerce could give you more, but it's also more demanding. You would need more time to make website in it (if you are not experienced with DC).
About D8 vs. D7 dilemma - IMHO, D8 is still not mature enough. Lot of modules are still missing, lot of them in alpha / beta state.
So if it's working and it's not making you any problems I would stick with it.