18M wondering if I made a mistake - need advice (Salam)

Assalamu alaikum. My name is Adam, I'm 18 now (was 17 during most of this). For privacy I'll use fake names - Sarah is 18. Back in 8th grade I went to a private Islamic school and met Sarah. We bonded quickly. We were young, but our connection felt real - innocent, caring, and respectful. We used to exchange long messages and support each other, and it felt special. Her parents were very strict about her not speaking to boys. They monitored her messages and eventually discovered our communications. They complained to my parents and the school several times. We were told to stop, but because we were so close it was hard to just cut things off overnight. At the end of that year her parents moved her to another school, and I moved too. I told her we should stop talking for now and that maybe in the future, when we were older and circumstances were different, something could happen. That decision hurt her a lot, and it still weighs on me. Her friend Khadija contacted me at the time because Sarah was struggling emotionally. I told Khadija she could tell Sarah whatever she needed to if it would help. Sarah even tried to get her parents to speak to mine, but my parents felt the whole thing was childish. I told Khadija my parents’ response: not now, maybe later in life. After that we had no contact at all. Now I think about Sarah whenever my parents bring up engagement or marriage. She was kind, modest, respectful, and had a pure heart. I keep wondering if I made a mistake ending things the way we did. Recently I spoke to a sheikh who knows both of our families and was involved back then. I told him the story and asked if he could check with her parents now that we’re older. I prayed istikhara about it. My parents don’t know I spoke to the sheikh. I still have her old email, but I felt it was more proper and halal to go through the sheikh and her parents rather than contacting her directly. I need advice: how do I cope if her family says no? Has anyone gone through something similar? I’ve been overthinking nonstop and even after istikhara I feel anxious and unsure. I haven’t told my parents or reached out to the mutual friend recently. I also don’t know how Sarah would feel about the sheikh contacting her family. Any advice, especially from people who handled a similar situation or from those familiar with Islamic etiquette around this, would really help. JazākAllāhu khayr.