for your mom to claim you as a qualifying child

• 1)  Same principal abode as taxpayer for more than ½ the tax year.  Temporary absences like for school are ignored
• 2) If not a full-time student, under 19 at the end of the tax year.  If a full-time student under 24 at end of tax year.  

         3) you haven't provided over ½ your own support

I would say test 1 fails so she can't claim you as a qualifying child but she could clain you as a qualifying relative if all these tests are mmet

• 1) your gross income for 2019 less than $4,200
• 2) she provided over ½ your support
• 3) isn’t a qualifying child of another taxpayer

i would say she fails test 2

however, your foster parents may be able to claim you as a qualifying relative same tests.

if they can you can't claim yourself.