Theres a child tax credit college students ages 19-24, where do i find this

There is not a child tax credit for a dependent age 18 or older.  There is an Other Dependent credit of $500 for those dependents.

There's an "Other Dependent Credit" of $500 for children over 17 (and other dependents), including full time students, 19-23.  This is given to you automatically when you enter a dependent in the personal info section of TT.  The money shows on line 19 of form 1040.  It is a non refundable credit (if your tax [line 18 of form 1040] is less than $500, you don't get the full $500). 

Separately, there is a tuition credit.  Parents claim it if the student is their dependent.