How long do your Sims live past their maximum life expectancy?

I don't know how or why but my Sim has been alive for something like 1349 days. I'm thinking now that it's a glitch? She's my first Sim - I just got the game three days ago! Ohhh god I love it- and she was progressing a normal Sim life, but then she wooed a hot chick and I was worried my Sim would die before we got married so I just maxed out all the lifespan dials and now she's over a thousand. I'm gonna go ahead and assume it's a glitch.