If Beyoncé is really 26, that would mean she joined Destiny's Child ( the group started in 1997) back when she was a teenager.
Think about it people. She DID NOT look like a teenager in the beginning of DC.
Also, "Say my name" was released in 1999. Now if you look at the clip, she looks like she is in her 20's, which would make her older thatn what she claims to be.