Kay, this is not stupid at all! I know how you feel, I've been thinking about that lately with Taffy. And today I was talking to my mom and realised my grandpa will be 70 soon. People and pets just don't seem that old until you think about it.

Simba has many, many, many, more years ahead of him. Your a great mom to him and you care about your dogs so much. Just don't worry about the future, just have fun with him everyday and enjoy your time with him.