Info on Enlarging on Canvas

[prtgm11]

Hi there, I am new to Photography and I have someone that has taken a liking to a Photo that I took, and they have asked if they could purchase it. I have no idea what to charge, have never charged before. Also, I'm worried that if the photo is enlarged and put on Canvas, it may not look the same, as in the resolution. Any ideas?????

I have tried uploading it, and it just says " undefined" ???

 

[KmH]

$2000