So I'm having a slight dilema here. I currently work at company that produces pharmaceutical equipment. I am the sole programmer at the company and am responsible for developing software that they use for generating reports, maintainence and so forth on their products.

For context, I just turned 21 and don't even have a college degree of any kind except for a certification.

Despite my current position being in the field I studied (computer science), I always had dreamed of working in a company closely tied with web application development. I recently found an open job position at a company that requires a PHP/MySQL developer for their back-end. I called them up today and directly spoke with the owner. I have an interview with him in the next two weeks once he comes back from his vacation (the company is relatively small, but growing).

My dilema comes down to this. My current employer just gave me a full time position starting at 40K when I threatened to quit about a month ago. If this new position at the other company was offered to me, I would feel a little guilty about it because I just started the full-time gig. If you were in my shoes and the company offered you the position at a salary higher than one I currently make, would you leave and take the offer? Or would you stay as a gesture of company loyalty?

My take on it so far is that loyalty is very valuable, and I will be loyal to the company that values my loyalty the most. However, I still feel very mixed about it.

Further context, the new position would offer a salary of up to $75k depending on my expierience, credentials and so forth.