No, no, and double no. Beginners is where all the foundations are created. It is the least appreciated and most important level. Do not start with beginners.
I sort of agree, for the person who is a serious student and will progress to advanced levels.
Yes, beginners should get a sound basis in the fundamentals early, or they will eventually be frustrated when they progress to advanced levels and find that bad habits are much harder to unlearn, or find that necessary skills have been skipped. On this I am in agreement with keypeg.
On the other hand, the percentage of beginners that will ever proceed to those levels is very small, and the percentage that practice enough to actually engrain any habits is also small. Many students are sent by their parents for enrichment or resume padding, and for them this doesn't matter as much. An enthusiastic beginning teacher may not have all the skills to start out the prospective conservatory candidate, but might teach a little piano along with a little fun and a lifelong love for music to everybody else, and over time will hone their teaching skills.
So yes, you are qualified to teach, but remember to do no harm, and improve your teaching with as much effort as you worked on your playing.