A PEG (percutaneous endoscopic gastronomy )is just a G tube that is put in with an endoscope. If you can't put the endoscope down the throat, then they use a fluoroscope and just put the G tube right into your stomach (like mine). The G tube itself is exactly the same no matter which way the doctors put it in but without the endoscope , there's no E and it's technically surgery if you use the flourscope and "operate" so no P (percutaneous). That's the difference between a PEG and a G tube.
At most places, you do indeed have a choice as to whether or not to get a feeding tube. I have heard of some doctors who insist on their patients getting a tube whether they want or need one, but I went to a CCC where the patient's decisions were honored. I was a stubborn old man who was determined to keep eating and drinking on my own. I ended up on a complete liquid diet halfway thru (Ensure Plus)but never needed a PEG and never got dehydrated or any complications.
Yes, several of us went through both radiation (8 weeks) and chemo without ever getting a PEG. We lost a lot of weight.
We used to have "PEG wars" here whenever this question arose, since feelings ran high on this particular decision. (I plead guilty since I over reacted when posters say a PEG is necessary as though many of us had not done fine without one) Many patients needed a PEG and are very glad they got one. I wasn't one of them. Since I now have a G tube for life (nothing to do with my decision not to have one the first time, but a result of the cancer coming back and surgery and even more radiation over the "maximum"); I'm doubly glad I went without it the first time.
On a practical note, if you can still eat, just don't use the PEG until you meet the nurse if you are worried about that.
You will get lots and lots of opinions here, but remember it is indeed your decision. As Nate pointed out, you can always get a PEG later on, but it harder on you then since you already feel so bad. My post is just my opinion also.

Best wishes
Charm