There are two types of dependents--qualifying child and qualifying relative. If you were 19 at the end of 2018 and were not a full time student for at least 1 day of 5 different months during 2018, your parents can't claim you as a qualifying child dependent. Since you made more than $4150 in 2018, they can't claim you as a qualifying relative dependent. So no you can't be claimed as a dependent by your parents.