I think your post is being misunderstood. You did not say the W-2 was from 2015--right? You said it is from two years ago when YOU were 15 years old. So---is that income from 2017 or 2018? You can still file a tax return to seek a refund if there is an amount shown in box 2 of the W-2 or an amount in box 17 for state tax withheld. Your tax return would be pretty simple to prepare on a paper tax form so that you do not spend money on tax software. Here are links to get the paper forms and the instructions for2016, 2017, and 2018--use the one for the year in which the income was received. The year will be near the top of the W-2.
Your parents could not put your W-2 on their tax return. Since you were 15 at the time you earned the wages, make sure you check the box that says you can be claimed as someone else's dependent. That will not prevent you from getting your refund if you have one coming to you.
https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment
PRIOR YEAR FORMS FROM IRS
2016
Form 1040 https://www.irs.gov/pub/irs-prior/f1040--2016.pdf
Form 1040 Instructions https://www.irs.gov/pub/irs-prior/i1040gi--2016.pdf
Form 1040A https://www.irs.gov/pub/irs-pdf/f1040a.pdf
Form 1040AInstructions https://www.irs.gov/pub/irs-prior/i1040a--2016.pdf
Form1040EZ https://www.irs.gov/pub/irs-prior/i1040gi--2016.pdf
Form 1040EZ Instructions https://www.irs.gov/pub/irs-pdf/i1040ez.pdf
2017
https://www.irs.gov/pub/irs-prior/i1040gi--2017.pdfhttps://www.irs.gov/pub/irs-prior/f1040--2017.pdf
https://www.irs.gov/pub/irs-prior/f1040a--2017.pdf
https://www.irs.gov/pub/irs-prior/i1040a--2017.pdf
https://www.irs.gov/pub/irs-prior/f1040ez--2017.pdf
https://www.irs.gov/pub/irs-prior/i1040ez--2017.pdf
2018 Form 1040, Schedules and Instructions
https://www.irs.gov/pub/irs-prior/f1040--2018.pdf
https://www.irs.gov/pub/irs-prior/i1040gi--2018.pdf
2018 Tax and EIC Tables https://www.irs.gov/pub/irs-prior/i1040tt--2018.pdf
IRS 2018 Schedules 1 thru 6 (only if needed)
Sch 1 : https://www.irs.gov/pub/irs-prior/f1040s1--2018.pdf
Sch 2 : https://www.irs.gov/pub/irs-prior/f1040s2--2018.pdf
Sch 3 : https://www.irs.gov/pub/irs-prior/f1040s3--2018.pdf
Sch 4 : https://www.irs.gov/pub/irs-prior/f1040s4--2018.pdf
Sch 5 : https://www.irs.gov/pub/irs-prior/f1040s5--2018.pdf
Sch 6 : https://www.irs.gov/pub/irs-prior/f1040s6--2018.pdf
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
