Mixed signals or not interested?

So I know this girl we went out two times (I knew her before that and some friends said she looks interested in you), the second time I told her I like you she said I don't know what to say and smiled. After that by a month we talked again (I usually prefer to talk in person) at university I told her is it weird I told you I like you? she said no but I think you weren't honest I said why she said we don't know each other that much but she always acts friendly and nice. we have a presentation at the university she insisted to come to mine and when she did hers I told her I will come she said more people will make her nervous but I went anyway after that I asked her did that make you nervous she said no but I don't know why did you come. I also sent her a follow on Instagram but she declined it although we have a lot of common colleagues.
So now I don't really know what to do on chat I always start the convo and she responds with long texts usually and chats but sometimes she just doesn't continue the conversation
should I send her a follow again on Instagram? should I drop the whole thing? should I tell her anything?
note: I told her you are beautiful two times and she just didn't say anything.
Updates
+1 y
Okay, I was thinking that my next step would be to tell her that I didn't get an answer and If she is not interested I prefer we be friends (which I mean, I won't think of her that way again) does any of you think that is correct?
Mixed signals or not interested?
Post Opinion