Should I reunite with a friend who I haven’t seen in 3 years?

My cousin said it was suspicious that the girl reached out to me this week when we haven’t spoken in 3 years. I first met her at a house party that a “friend” from uni had for her birthday, which was 3 years ago. And as of recently, the girl has been talking to me. She mentioned that the reason she connected with me again, is because she was going through her old pictures on her phone, and wanted to know if I was well. When we first met at the house party that time, we truly connected & had a good time and did take many selfies together. We last exchanged messages 2 years ago when we were both busy with uni, and the corona madness disrupted us re-connecting summer 2020, so we’ve just been focused on our uni work.

My cousin also thinks it’s suspicious that she’s invited me to her birthday celebration this weekend , and says that it’s weird that I haven’t mentioned about the girl before to her, and at all. My cousin also thinks it’s dodgy that she’s reached out “all of a sudden” and fears if I’m the only one going to her birthday celebration that I shouldn’t go.

I know my cousin is just looking out for me. But if she really understood my experience, I haven’t had a close friend in my life since college ended in 2018.
My uni experience was poor, and so is my current job experience. I have NO friends. I’ve made countless bumble BFF profiles for 2 years, hoping that I’ll meet or connect with someone, just to not go with plans bc my family will fear my safety. I’ve ruined what I find good connections with the people on these apps, just to not meet up. It’s been making my life so miserable how bored I am with my life bc I have no friends, I’m questioning my sanity everyday, thinking there’s something wrong about me. I just feel so hopeless and I’ve come to an conclusion that making friends in your 20’s is completely difficult and I don’t see have any friends past your 20’s is doable.