The Bible should always be your ultimate authority. It should take preeminence over what anyone thinks, including mom and dad. Never should we despise anyone. As for dealing with social issues, Let's take a look at a few scriptures.
Romans 3:29
Is God the God of Jews only? Is He not the God of Gentiles too? Yes, of Gentiles too,
(Is he the God of Republicans only or democrats only?)
Galatians 3:28
There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for you are all one in Christ Jesus.
Yes the above is talking about those in Christ; but, if we look deeper into this scripture, we would see that God is no respecter of persons. Your social status means nothing to Him. He looks at the heart and even if you heart isn't right, he yet remains a merciful God.
1 John 3:15
Everyone who hates his brother is a murderer, and you know that eternal life does not reside in a murderer.
1 John 4:20
If anyone says, "I love God," but hates his brother, he is a liar. For anyone who does not love his brother, whom he has seen, cannot love God, whom he has not seen.
Deuteronomy 15:11 (also see Matthew 14:7)
"For the poor will never cease to be in the land; therefore I command you, saying, 'You shall freely open your hand to your brother, to your needy and poor in your land.'
And as for those who abort babies, are homosexuals, believe in the use of marijuana or what have you. Remember the scriptures says:
"Behold, the LORD'S hand is not shortened, that it cannot save; neither his ear heavy, that it cannot hear: (Isiah 59:1). It also says that WHOSOEVER SHALL CALL UPON THE NAME OF THE LORD, SHALL BE SAVED.
Mercy and grace are extended to anyone who repents. We did and they can too! Therefore, look down on no one. If your mom is a professing Christian, you are not too young nor will you be out of place to correct her. Let her know i a respectful way that you are choosing God's way!