But unlike her classmates, Caitlin has Dubowitz syndrome, a rare genetic condition that causes developmental delays.
Dubowitz syndrome is known to affect only about 200 people worldwide.
It is thought that Dubowitz syndrome is an inherited genetic condition or chromosomal mutation, but no formal test exists beyond the physical examination.
Funds raised will be used to raise awareness, increase research and advocate for more support for those with Dubowitz syndrome.
Now preparing for her first Boston Marathon, the West Boylston resident said when she reaches Newton's famed Heartbreak Hill, around mile 20 on April 21, her motivation won't be to say she simply finished the race, but that she did it for her niece, 7-year-old Caitlin Granger, who at 2 years old was diagnosed with the ultra-rare Dubowitz Syndrome.
Less than 200 people worldwide have been diagnosed with Dubowitz Syndrome, according to Caitlin's mother, Megan Granger.
Dubowitz Syndrome cannot be picked up on blood tests, it is diagnosed visually.
Some doctors think Dubowitz Syndrome is hereditary and that it develops when two carriers of the gene in question have children.