Have I been making a big mistake using "oldest"

[alcush]

I have two children. I have always referred to my child born first as my "oldest", and my child born second as my "youngest." My brother-in-law recently corrected me saying I should be using older and younger because there are only two kids. That makes a lot of sense, but my quite intelligent sister disagrees. Which is correct; older or oldest?:-?

 

[5jj]

Strictly speaking, 'older' or 'elder' and 'younger' are. correct.

 

[Raymott]

Which is correct; older or oldest?:-?

Elder and younger.

 

[alcush]

I am really upset that I have been wrong all this time. LOL! Man, that burns me! Well, I will never make that mistake again. Thanks! ;-)

 

[5jj]

][/SIZE]I am really upset that I have been wrong all this time. LOL! Man, that burns me! Well, I will never make that mistake again. Thanks! ;-)

Some native speakers make the same mistake. It's not serious.