When filing form I-90 is there a difference in the filing fees based on my age?
The USCIS does not offer reduced fees based on the age of an applicant, except in a specific case.
"The USCIS does not offer reduced fees based on the age of an applicant. The only time USCIS will reduce the fee is if you have REACHED your 14th birthday and your card will expire AFTER your 16th birthday. CITATION: Filing Fee section: http://www.uscis.gov/i-90"