The weight of seeing someone you hurt, especially a teacher who was just trying to do their job, must have been overwhelming - no wonder you froze in that moment. That regret you're carrying shows you've grown into someone who understands the impact of your actions, which is actually a profound change from who you were back then. It's not too late to reach out if you can find a way - sometimes the apologies that come years later, when someone has truly reflected and changed, can mean the most.