I'm a bit confused now, should I neg her or not?

Anyway, how do I know that I can start kino after teasing(you said that I need to put all of my effort on talking then on kino...).

About what you've asked, she's absolutely not a bitch, but its hard to describe her with these two description. You said that cutie has lower ego and less going out, SHE ISNT LIKE THAT, she go out, having fun, having fun with boys, drink, touch, being touched, so I don't know if you can call her cutie as you described it.
But she does act cute toward other people, never become bad person(at least as I know her...).

don't make it so tough or complicated on yourself, just be your normal you

next time you see her, out of the blue just ask to see her hand, if she doesn't give it to you then tease her, if she asks why just say ''to see your hand obviously'', if she gives it up just hold her hand

if it feels awkward you can just kill the tension by saying something like, ''see, now we are holding hands, isn't this special'' and smile, you can just keep taking it further from there, or if that was a huge leap for you just get comfortable with that, what ever suites you

just try to stay in a good mood with a nice big shit eating grin on your face like you are a kid in a candy store, have some fun with it and don't worry so much, she is not going to kill you cause you like her and she probably already knows what you are afraid to express

if you need any justification for anything, the only justification you need is that you like her, more honesty, less hiding behind deception

you are extremely unlikely to pull anything off in some sneaky covert way, the only way you will end up having consensual sex with a girl you like is if she wants to end up there too, and at some point someone is going to have to express some intent to do so, if hand holding is too much for you, imagine how hard it is going to be to kiss her for the first time or get naked together

no risk, no reward, just work up all the courage you got and put your ego on the line, what do you have to lose?

at least if you try something, you have a chance of anything happening, every time you don't try, you will always fail