Galatians 3 26-29 neither jew nor Greek

xThere is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus.
Gal 3:29
And if you are Christ’s, then you are Abraham’s seed, and heirs according to the promise.

But does becoming a Messianic make you a Jew and do you receive all of their promise