When to reveal stutter to a girl I met on a dating app?

I have a low to moderate stutter (severity is completely random on any given day). So I been talking to this girl I met on this dating app. She lives somewhat far from me (2hr30min flight). We been texting back and forth on the app. Recently moved to snapchat. And probably will exchange phone numbers soon. Due to the long distance we probably won't be meeting in person for quite some time. When should I tell her about my stutter? I Kind of want to tell her now, in case it is a deal breaker and I don't want to waste each other's time. If it is a deal breaker I would totally understand, nothing personal. Or should I wait to tell her right before we take the step to talking on the phone, which might not be for some time (who knows). Any advice?