Her justification is from Genesis 1:14: "And God said, 'Let there be lights in the expanse of the heavens to separate the day from the night. And let them be for signs and for seasons, and for days and years.'" She says, "I feel that astrology was a tool created by God for us to understand ourselves better and to use as a spiritual tool. I feel that there are many biblical verses that support astrology." Notice her words, "I feel," not once, but twice. That is, her use of this verse (she also mentions Luke 21:25) isn't based on exegesis, an interpretation of the verse using grammar and its historical and biblical context, but rather on her feelings. That is always the start of syncretism, because "the heart is deceitful above all things, and desperately sick" (Jeremiah 17:9).
What does exegesis teach us about the role of the stars? Consider the case of Esau and Jacob, the twin sons of Isaac (Genesis 25:19-28). As twins, the two were born under the same planetary and stellar positions, the very things that are supposed to be determinative, according to astrologers. Yet, what do we know about their futures? "Jacob I loved, but Esau I hated" (Malachi 1:2-3, Romans 9:13), polar opposites. Paul uses these twins, born under the same astronomical circumstances, as a case study (Romans 9:16): "So then it depends not on human will or exertion, but on God, who has mercy." That is, Esau and Jacob don't tell us anything about the planets and stars, but rather about the sovereign grace of God.
And that's the problem with astrology. It posits ultimate sovereignty, not in the hands of a living, just, and loving God, but rather in the paths of stellar objects, though they, too, owe their existence and positions to that God (Genesis 1:14, Job 9:8, Zechariah 12:1). And God has no tolerance for giving His glory to anything or anyone else (Isaiah 42:8, 48:11). In fact, He rejects anyone who tries to do so (Deuteronomy 29:18-20): "Beware lest there be among you a man or woman or clan or tribe whose heart is turning away today from the Lord our God to go and serve the gods of those nations. Beware lest there be among you a root bearing poisonous and bitter fruit, one who, when he hears the words of this sworn covenant, blesses himself in his heart, saying, ‘I shall be safe, though I walk in the stubbornness of my heart.’ This will lead to the sweeping away of moist and dry alike. The Lord will not be willing to forgive him, but rather the anger of the Lord and His jealousy will smoke against that man, and the curses written in this book will settle upon him, and the Lord will blot out his name from under heaven."