I think I'm just going to say no
What is the reason why you are saying no?
I'm a person who always commits myself to a cause.
Its fine to say no sometimes if you dont feel that yes would be the best option for you. Sometimes you have to think about yourself when making decisions and this may be one of those instances.
The thing is that I am not 100% sure that this is the best thing for me, but I am leaning towards no.
If you are leaning towards no, don't you think that you should just say no then? You don't have to be 100% sure about your decision. You should just make the decision that is best for you!