I don't know enough about the Nautilus to comment. We have Regents and love them. Our DD is 4.5 yo, 40 lbs and 42 inches tall.
Here is some interesting info on how the average child grows.. height and weight:
Your child should gain about 5 1/2 to 7 pounds each year. Girls have a growth spurt between ages 9 and 10 and boys usually catch up by age 13 or 14.
Your child should grow in height about 2 to 2½ inches each year. Your child's long bones (the ones in his legs and arms) slowly get longer.
Site quoted from:
http://www.drugs.com/cg/normal-growt...-children.html
A couple other good sites:
http://www.cincinnatichildrens.org/h...o/growth/well/
http://pediatrics.about.com/cs/weekl...032002_ask.htm
http://www.childrensnyp.org/mschony/nrmgrth.htm
Those links above have some really good growth charts...
Kelle
Mom to Riley (05-03)
(She's a girl, not a boy)
Used to sit in REGENT
NOW SITS IN FRONTIER
WE LOVE!!!