Hi, In January 2019, I was working full time making 55k a year. I decided to go back to school in October 2019. Am I considered a dependent of my parents?

[SteamTrain]

1)   For 2019 taxes...almost certainly not a dependent  (your age at the end of the year has meaning here, but I suspect you are age 19 or older by 31 Dec 2019) .  And, if under age 24, you must have been a full-time student in college for at least  5 months of 2019 in order for your earnings to be ignored.....and you made more than $4200 in 2019.

2) For 2020, if you still are under age 24 by the end of 2020, and full time in college for at least 5 months, they could claim you as a dependent if they provide  more than half your support during the year (ignoring scholarships and grants)...but there are subtleties to the support determination.

[SteamTrain]

Here's the list of dependency rules for your parents  (living at the college counts as living at home).

https://ttlc.intuit.com/community/credits-and-deductions/help/who-can-i-claim-as-my-dependent/01/267...