12 is a good age for a pup..I know a lot of breeds dont even live to 10 years old..mastiffs for one have an expected lifespan of about 7-8 years..some last longer of course. But I'd say you had 12 good years with your sweetie and you have many wonderful memories no doubt :).

OOH and I look forward to meeting you and your husband at AC :)..he has told me nice things and from my few interactions with you, you seem absolutely wonderful!