You cannot receive stimulus money for a child older than 16.   Check the date of birth you entered for him in My Info.

$1,800 would be the wrong amount anyway.  Or are you doing his return for 2020?  He might need to check the box under My Info that says he can be claimed on someone else's return.

If you are doing your return you get 1200+600 for you.  Did you get any of the Stimulus payments?

Or if he is doing his 2020 return and is not a dependent for 2020 then yes he gets it for himself!

The Stimulus Checks are really based on your 2020 return we are filing in 2021.  So any amount you already got will be reconciled on your 2020 return line 30.  If you didn't get a Stimulus Check (and qualify) or you qualify for more it will be added to your 2020 return.  But the good news is if they paid you too much they won't take it back.

Filing for myself as a non-dependent (can't be claimed on another's return) for 2020.

However, my understanding is that since I was 16 January 1 of 2019, that my parents were eligible for the dependent stimulus, which they got in 2020.

For the 2nd stimulus, I tried searching the IRS site and it gave back no information, which I assumed was because I wasn't eligible and my parents would still get a dependent amount.

When filling out my 2020 return, it asked if I received either the first of 2nd stimulus payment.  I said "NO" and it stated that I was due $1,800 ($1,200 + $600).  Now based on the Stimulus eligibility, I shouldn't be getting anything and I want to avoid any future issues with my return or my parents.

Oh, you are the 19 year old and the dependent?  We were answering like you were the parent.    If you are filing your own return and not as a dependent then yes you get both amounts even if your parents already got it for you.   So you both  get it.  Are you 19 or 18?  You said you were 16 on Jan 1, 2019 which would make you 18 now.  

I was 18 as on Jan 1st.

I turned 19 in the 2nd week of January.

How does this work for the 3rd payment? We received $1400 for our dependent daughter but she is not a dependent for 2021. Does she say she didn't get the 3rd stimulus when she files her 2021 taxes? And we say we got $4200? 

Yes exactly.  She didn't get it, you did.  She can get it on her return.   And you don't have to pay it back.