If you intend to keep it simple & small, none of the following advice really matters. Two people can work together on anything. This is about what happens when you need to hire that 2nd, 3rd and 4th developer, sales team, etc. because you are starting to feel the burnout monster lurking in the shadows.
I'd say your job is to serve the board (CEO) + developers as a sort of communications bridge and secondary captain. You should try to steer the technology away from things that would add complexity/liability to the organization. You should always be asking: "How does this add value to the customer's experience?" followed immediately by "Don't we already have XYZ at home?".
Certainly, let your developers play with shiny things from time-to-time, but carefully pick & choose the technologies that you promote to "we use this in prod for paying customers". Consider that this may have implications for the technologies you select today. Everything in technology has inertia, even if it's just files in the computer. That fancy purely-functional web framework you really enjoy today might not be so compatible with the broader job market tomorrow.
> I am trying to figure out if I'm capable enough to be a CTO.
I think many CTOs are still trying to figure this out today. For me, the struggle never ends and I think that is sort of the hallmark of good leadership. If you become content & comfy in your seat of power, you are almost always headed down the path of cartoon villain boss and/or bankruptcy.
Humility is probably the most important thing. The ability to put your ego into a box, lock it, and throw away the key for 5+ days a week is critical. If you cannot do this, you need to consider if CTO is a good path for you. Especially if you intend to scale beyond just the CTO being the only developer in your organization. Growing other people is the hardest thing. They have egos too. You can get value out of almost anyone when they feel empowered.
You may find value in adopting an "extreme ownership" mindset, but others on HN have different opinions of this sort of thing. I've gone down this path and I enjoy it because the fire of "everything is my responsibility no matter what" has encouraged me to push my team away from things that would cause me to lose sleep at night. My fears happen to be highly-coincidental with our customers' fears, so this tends to work out well in practice. YMMV here and I am not responsible for any side effects that may result from reading certain "self-help" books...