Applying for new B1/B2 visa with new passport, the birthday on my new is different from my old

It can be an issue, and it can be overlooked even when noticed. No definitive answer. The consulate knows there are problems with birthday, name spellings, and other discrepancies in applicants data. Have a good and coherent explanation when it comes up. If they smell fraud however, you could be in trouble including being essentially permanently banned from visiting the USA.

Having secondary evidence like old school reports and medical records or baptismal certificate etc which show the correct date consistently is helpful. An affidavit from an official or a priest etc are also acceptable.

From USCIS Adjudicator's Field Manual Primary and Secondary Evidence

Closely related to the best evidence rule is the concept of primary and secondary evidence. Primary evidence is evidence which on its face proves a fact. For example, the divorce certificate is primary evidence of a divorce. Secondary evidence is evidence which makes it more likely that the fact sought to be proven by the primary evidence is true, but cannot do so on its own face, without any external reference. In the above example, church records showing that an individual was divorced at a certain time would be secondary evidence of the divorce.

By evidence (such as an affidavit)

By a written statement from the appropriate issuing authority

Your young age should be somewhat helpful since you were a minor and not responsible for these mistakes.