18 months, my tuchus by elevins | Aug 27, 2010 | 03-06 Months This shirt that Grammy got me is size 18 months… I’m only three months old, and I’m not an amazon, so I don’t know what these people are thinking. I do like my outfit today, though… Even though the people who put the sizes on it are on crack. Related Posts I'm 18 months old today!Mommy says this is a pretty big deal! I'm 19 monthsToday I'm 19 months old. Dad decorated Ernie. I went to visit him. YumJust ate. Feelin' good. Chillin' with mom.