How do i say this

So awhile back i came on here to find out how i should ask a girl out. I finally did it and she turned me down saying she was talking to someone but she would’ve definitely say yes. It’s been like 3-4 months and she has since texted me back. She said she’s ready to start a relationship. I have a few issues though. I don’t really enjoy the feeling that I’m her second choice. Also in these few months I’ve realized a few things about her. I found out through tweets that she likes/ retweets that pop up in my timeline that she suffers from depression. She is also bi sexual and likes a lot of posts about how “men ain’t .” Finally, I’ve concluded from the tweets and her ex boyfriend that she smokes weed. Also, she has since cut her hair to above shoulder length. Maybe if it was one or two of those listed changes I’d be fine but with all of those factors, i don’t think she really fits the girl to fill my fantasy high school relationship with. How do i let her know that w/o upsetting her?

Just say that your feelings have changed. You don't have to volunteer any details. It's not a good idea to tell her anyway, because even though your opinions are completely subjective they could hurt her feelings. If she asks you what changed, just say you see her more as a friend now.