I find myself in an interesting situation and I hope I could get some advice:

I'm currently enrolled in a 2 year diploma program at a technical institute. During the summer, between year 1 and year 2, I worked for a company in my field of study. I enjoyed working for said company, and I left a good impression.

Just a few days ago, they asked if I was interested in a job offer for when I graduate. Assuming that they would extend the offer when I actually graduated, I said of course! HR replied back saying that they would be sending me the offer within the next few days (!).

Now, here's my question. I graduate 7 months from now. I want to keep my best interests in mind, and evaluate all of my options. I have not interviewed for any other company in this industry. Would you accept this offer in my situation? I've done some research online for average starting salaries, etc. If I do accept the offer now, is it wise to continue to send out resumes and "test the waters" for when I'm actually on the job market? If so, should I let them know that I'll be doing this? How could I communicate that professionally?