How to tell someone to stop talking to you so much, but in the absolute nicest way possible?

I recently got in touch with a childhood friend I haven’t talked to in about 10 years, and I only meant for us to maybe follow each other on Instagram and be casual acquaintances but she’s taken it way too far and now she enthusiastically texts me multiple times every day without fail to send me between 3 and 10 posts she thinks I’ll like, and I always respond with one word answers and lately I’ve started to not respond at all sometimes, and it’s such a chore to open her messages 3 times a day and try to act enthusiastic back, because honestly she’s a sweet person, she’s just not the kind of person I want to text EVERY SINGLE DAY. She also kept obsessively asking me to hang out with her (I kept saying I was busy) until I was kind of forced to accept her invitation to Homecoming in September (which I still don’t want to go to). She requested to follow my personal Instagram (where I only accept close friends), and I felt bad for denying, but I denied her TWICE, and she tried again, texting me, “I followed your personal Instagram :)” (I didn’t respond), and after I denied her for the third time, she asked “do you still use your personal Instagram?” (I didn’t respond again). And to make things worse, she and her mom are so excited that we finally got in contact again and she’s just so happy for us to become super super close, but this is all giving me so much anxiety and I don’t want to say anything that might hurt her feelings and I just don’t know what to do.