Does this mean my baby will be a big baby ? Or be born a week early? Or am I farther a long? Lmp says I'm 26 Weeks but measurments say 27..

All babies grow at different rates. Basically the only constant is how their organs mature.

Do you have gestational diabetes? Are you a diabetic?

One week either way... your EDC puts you at 26 weeks and the scan puts you at 27 weeks, is of no concern as the average is two weeks either way.