It should be fine - is it an Instamatic (126 film) or a Pocket Instamatic (110 film)?
Not many places develop 126 or 110 anymore but this place here does:
http://www.photofilmprocessing.co.uk/110filmprocessing.html
I've not used them before yet, I literally just sent off my 110 film from from my Pentax Auto 110 to them this morning.
If however you want to have a greater chance of usable images, then you could use Process C-22 who specialise in old/obsolete film types and processes such as 126, Disc film etc:
http://www.processc22.co.uk/
Be warned that they are twice the price and are known to take a while to get it back to you.