Romans II
… but God shows his love for us in that while we were still sinners, Christ died for us. (Romans 5:8 ESV)
Teen-aged boys, I have observed, usually like a girl second, not first. The number one reason I hear for attraction in young folk, is that someone (the beliked) laughed at our jokes, smiled at us first, spoke to us first, seemed to like US, first. THAT is why we become interested.
I might be wrong, of course. Apocryphal evidence abounds.
But clearly, we love God only because He loved us first.
In fact, we can not love God without His love, because His love sent Christ to die for us, before we ‘accepted’ Him. And that Christ-sending is what changes us so that we CAN love God.
He loves us, so we love Him.