how do i politely tell a girl i don’t want to hangout and just stay mutuals?

for context, she is a grade higher than me and goes to a different school, but we are both mutuals on instagram so we are connected that way. a few months ago, she started replying to my stories, messaging me about our shared interests, sending me posts, etc. at first i didn’t mind much, i have mutuals who i interact the same amount with who im not friends with in real life. recently though she has been texting everyday and constantly asking to hangout. maybe i sound like an asshole but i really am not interested in being friends outside of instagram, especially because of the fact we don’t even go to the same school. how do i politely shut down her asking me to hangout?

apologies for an uninteresting post😅i just feel very stuck and do not know what to do