If she is not a full-time student then you cannot claim a child who turned 19 before the end of 2020 and who had over $4300 of income

WHO CAN I CLAIM AS A DEPENDENT?

You can claim a child, relative, friend, fiance (etc.) as a dependent on your 2019 taxes as long as they meet the following requirements:

Qualifying child

•They are related to you.

•They cannot be claimed as a dependent by someone else.

•They are a U.S. citizen, resident alien, national, or a Canadian or   Mexican resident.

•They are not filing a joint return with their spouse.

•They are under the age of 19 (or 24 for full-time students).

• No age limit for permanently and totally disabled children

  •      They live with you for more than half the year (exceptions apply).

Qualifying relative

•They don't have to be related to you (despite the name).

•They cannot be claimed as a dependent by someone else.

•They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.

•They are not filing a joint return with their spouse.

•They lived with you the entire year.

•They made less than $4300  (not counting Social Security)

•You provided more than half of their financial support. More info

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.

Related Information:

•Does a dependent have to live with me?

•What does "financially support another person" mean?

•Can I claim a newborn baby?

Is yiu 19 yer old a full-time student?    If not then she is too old and earned too much to be a dependent children grow up and can no longer be a dependent.