Congrats!!! Wow i've never heard of anyone else coming close to the birth weight my daughter was. Mine was 10lbs. 3oz. also 54cm. Sounds like it went very easy for you, you are so lucky I stopped dialting, I had to have a c-section.
You will love having a big baby 
they don't feel breakable and in my case she ate 3-4 hours not every 2 and looked 2 months old LOL
My daughter is 7 days shy of 8 months old, very tall and and slim. She hasn't even doubled her birth weight yet but is in the 75th percentile at 18.8lbs.
Again, congrats! Our bodies brewed them up nice n' healthy! (My daughter has never been sick btw!)