guitarhero30

Not you as a child but your parents or guardians were supposed to know. 
 
Anyway, provide the mentioned worksheet with all the corresponding dates along with any evidences you can get like stamps, tickets and such.
 
 

Sounds like that is the issue

Was the visa used in 1999 a new visa? Because the first one was automatically cancelled per INA 222(g):

It probably doesn't negatively affect it, but confirm this with an experienced immigration attorney.
 
From my understating, you still meet the Inspected and admitted requirement with the 1999 entry through POE: https://www.uscis.gov/policy-manual/volume-7-part-b-chapter-2 (And the bars seem to not apply in your case: https://www.uscis.gov/laws-and-policy/other-resources/unlawful-presence-and-bars-to-admissibility)

They most likely want to verify your age, plus check all the dates of entry/exit to make sure your timeline on the AOS application align with the worksheet.  If you entered legally, they should have a record of it, so try to submit correct dates.  Good luck!

You are absolutely correct. I have some knowledge about this including reading a case where an immigrant entered and adjusted status etc using an automatically voided visa without his knowledge. 
 
It was ruled that it still qualified as lawfully inspected and admitted (being waved in by a border immigration officer was also determined to be lawfully inspected and admitted in another case).

TL:DR
 
A separate question that wasn’t addressed was, in the waved in situation, what duration of stay does such an admitted person get. My belief is that would be an indefinite period of stay authorized by the Secretary.😁

They do not have a duration of stay

https://www.uscis.gov/laws-and-policy/other-resources/unlawful-presence-and-bars-to-admissibility "Minors: Children do not accrue unlawful presence while they are under age 18."
 
Also, you haven't left the US after you turned 18, so the 3-year and 10-year bars have not been triggered. Thus you should still be able to AOS.