Is 26 years old too late to try to get into the music business?

I have been really ambitious and driven lately to try and chase my dream of having a music career. I have been singing my whole life, but just recently I started taking it more seriously. Some friends of mine told me I'm too old for that type of career. I just turned 26 and I know most record companies are looking for the next teen sensation, then on the other hand, there are plenty of new singers coming out. I think Bruno Mars is 25. Even if I don't become "super-famous," I'd still like to do something involving music/singing. It just makes me happy and nothing else really appeals to me. I already have a backup career if it falls through, so I don't see what's wrong with trying. I was hoping to get some advice from people who are already out there doing it, about what to expect, what I should do to help my chances? I just sing, but I'm learning guitar. Should I write my own songs for a demo, or can just singing a cover be enough to send off to a record company? Should I relocate to a more music oriented city (I live in Ohio, near cleveland). I would love to be as successful as Colbie Caillat. I really admire her. Please give me some constructive advice.