(RNS) When President Obama announced his support of same-sex marriage, I was thrilled. But I also was filled with a sense of dread about the maelstrom that was sure to follow. I knew it was coming because there was a time when I would have been a part of it.

This Friday (June 15), I'll be at the White House for a reception to mark gay pride month. It's an event I never thought I would be attending.

The night my 37-year-old daughter Cholene called and told me she is gay, I felt as though the air had been sucked out of the room. I was beyond devastated. I had been an evangelical Christian for more than 30 years and thought that this was the worst thing that could happen -- to a parent, to a Christian, to me.

Cholene had given us many reasons to be proud of her -- she was a graduate of the U.S. Air Force Academy, the second woman to fly the U-2 spy plane and then a captain for a commercial airline. In my experience, "gay pride" was not on the acceptable list of parental bragging rights.

I begged God to change her. But instead, God changed me.

I had always known that I had a problem with unconditional love, but I thought if I followed all the "rules" and "worked" for God and his Kingdom, I would get a pass on the love thing. I didn't.

In 2004, Cholene emailed me to say that she and her partner were getting married. I didn't take it well at all. One morning as I was driving to work, I actually asked God, "What event could a parent be asked to attend that would be worse than this?" His answer was short -- a funeral. That got my attention.

By the time we arrived in Massachusetts for Cholene's wedding, God was already there. I have never felt his presence and love as I did that weekend-perhaps because it was so unexpected. It was then that my heart began to change. I told Cholene that her wedding rocked my world, and my world needed to be rocked.

I have learned since then that Cholene knew she was gay ever since she was a little girl. She got the message from pastors, Sunday school teachers, Christian leaders and even her parents that she was an abomination to God and didn't deserve his love. I have agonized over this. People have said, "But you didn't know she was gay." What difference does that make? Our behavior was unconscionable, not only as parents, but also as Christians.

Thankfully, she received the message from God himself that he loved her.

I have had a dramatic change of heart since first learning of Cholene's homosexuality. Call it a paradigm shift, an epiphany or just plain coming to my senses. Whatever it was, I know this-God was behind it. I would give anything to have a do-over for those years when we hurt Cholene so terribly, so I'm on a mission to help keep other families from making our mistakes. Our story did not end in tragedy as so many do. But it could have.

I can't forget where I was before. My thinking is so different now that I find myself being upset with those who aren't "there" yet. Now, the lessons I have learned about unconditional love for the gay community need to be applied to those who are exactly where I was for so many years.

Love can't be legislated, politicized, forced or faked. It comes from God. I have said many times that change will come one heart at a time, and only God can change a heart -- if we will just get out of God's way.

(Shari Johnson is the author of the recently published memoir "Above All Things" and serves as the president of the local PFLAG chapter in Odessa, Texas.)

KRE/LEM