Why do you think non social media presence is a flag?
I find it refreshing that she doesn't have a million socials or heavily invested in that. Most women are these days. If not or they're also on dating sites checking notifications from DMs, text messages from orbiters, etc. Sometimes they're family and friends, yet many are orbiters or exes vying for attention from her.
Use old fashion screening tactics to uncover what you want to know about her if you're seeing long-term potential.
How long have you been dating this plate? For now, focus on having fun, taking her out on dates, escalating and seeing where things go from there.