Should I leave my "first" job for a PhD student position? I graduated from a masters degree half a year ago and I am been working at a private research institute. Today I received an email from a professor who is asking me to join him in August this year for an graduate position in the experimental sciences. If I accept, I would have to quit this job before the contract terminates, which I think may spark off some negative consequences in the industry, such as a marred reputation. I tried to make the best out of this situation by asking the professor whether I may defer admission for 6 months so that I finish my contract before I start. He said it won't be possible to defer, and advised me that I will have to apply again next academic year if this was the case. 

I've previously had 2 years of resaerch experience as a research assistant, and the sole reason I think I need to do a PhD eventually if not now is because I want the rigorous technical training that only a PhD program can offer. 

Pros for doing a PhD now: 


I want to do it now in my early 20s as I think it will be more difficult as I get older (physically, or even mentally.
It is a rare opportunity that I get an offer since I had an egregriously low GPA when I was an undergraduate. I may not get this opportunity again. 


Cons for doing a PhD now: 


I am doing well in the private research institute I am in now, and I am responsible for a project that is not yet finished. 
Quitting my job after just 10 months will not look good, and may raise issues with the HR in the future. 


What do you guys thinks?
You did not mention how do you feel in your current job. Do you feel that you are learning a lot, are you enjoying it? If the answer to this is yes, and seeing as it is a private research institute, then maybe consider staying there. There has been a lot of articles around about how you do not need to have a PhD to be successful and satisfied in your career. 

Another point to consider is, why did you get this offer despite your GPA being so low? And maybe your GPA being low is an indication to you being able to grow more in a job at a research institute, as the environment, different from academics, may suit you better and you would end up learning more here. Or maybe your GPA is low for other reasons, and it does not always reflect how you strive in a PhD program anyway.