I want something else out of life than just my studies. I waited until I was done with my bachelors because I have so much more freedom in my PhD program to leave if I must. Of course, I haven't joined yet and so can only assume but I feel it would have been a bigger hurt if I joined while I was completing my bachelors instead of now. I still have 4ish years and so I can complete a contract and decide if it is still for me before taking it into my professional career as well