Do you think I need a cofounder?

I think it depends on your goals and needs. Where do you want the biz to be in 6 months, a year, three years? What skill sets do you need? As a developer, I've really benefited from bringing on a really good marketing head as a minor partner. My skills lack in that area, and with two people things get done faster. Just having someone else to work with day to day who is really invested is a huge accelerating force. Advisors aren't the same thing. If you can find someone you know has the skills you want and is go-getter enough to be a partner in a startup, that might be the best way to go. Nice site! Good luck.

I once worked in a particularly good position where the owner (my boss) would repeatedly say something that stuck with me. He was proud of the fact that he had been able to 'hire people who are smarter than me'.

That got me looking at my co-workers in a different light, and indeed, there were several people who worked with me, and they were each better at something than the owner. I realized that by hiring this way, he got to take the credit for a remarkably well-oiled machine that was able to get all sorts of things done exceptionally well. We all did the impossible & it was because of each of our points of expertise worked in synergy- like a puzzle coming together.

So, based on this experience, I would wholeheartedly recommend that you find someone- doesn't have to be a co-founder, could just be an employee, to work on something where your own talents are 'less' (for lack of a better word). Someone full/part-time who's dedicated to business development I would imagine would be a valuable asset.

I learned from my own (failed) startup, that the unexpected is guaranteed to happen. And if you need to allot your time & attention to something else that suddenly comes up, it'll help to have that someone around to help bear the load.

-my 2 cents. Best of luck!

This is cool and it's great you are getting into it while you are still in high school! I think bring someone on is a great idea. I have started a few micro/small businesses, and generally it's more fun and good to have someone to bounce ideas off of / help with the ups and downs.

Is the company making money, or is it a free service? Co-founder could be a good idea if you have a friend that you think could be helpful. If not, you could hire someone reliable (maybe on commission?). Or offer a % of company, base on performance. Just a few ideas - for what they are worth - best of luck!