Yes. For some students you will be too large.
To be fair, you can do whatever you'd like. If this is truly your passion, go for it.
However, I would not want to take lessons from you in a 150/52, or even a 172. These planes are cramped enough for two people, much less a larger person like yourself. After the first flight I would probably be looking for a new instructor.
For a new student, the cramped cockpits with a normal instructor take some getting use to. People are generally use to a certain amount of personal space. The first time you get into a cockpit and realize you are crammed into this tiny space, and rubbing shoulders with someone you don't know, is uncomfortable. This can create additional anxiety for new students.
I've been flying for 30 years and I still don't like taking a flight review with someone I barely know.
I think this cramped feeling of rubbing up against a stranger adds to the stress of a new student, and this is for a normal size person. Someone your size is going to make the cockpit feel claustrophobic.
A secondary consideration will be your weight. It will add to the difficulty of all maneuvers, especially if you are training in a 150/52. The larger the aircraft the less impact but in the smaller ones, it is a consideration.
If you want to be a CFI, you should go for it. Just be aware that some of your potential students will have some of these concerns.