How can I find out 100% if I'm bisexual?

Ok here is my problem I am a16 years old girl and I am like 99% sure I am bisexual no big deal. My problem is that I don’t know how to figure out 100% also I was kissed for the very first time like half a year ago by I guy I really like he was also my best friend so I thought. 5 seconds after we kissed he asked me to have sex on the floor at are school because that were we were at the time. I started coming up with excuses why I wouldn’t do it. Then I final said give me a couple days to think about it. Well I told him no 2 days later now he wont even talk to me. Did I do something wrong? When I final asked him why is he being like this? He said why don’t I just go f$#k a girl. I am scared he is going to tell every one I am bisexual and the thing is I am not fully out of the closet. Please help me. I know there is a lot of info here and a lot of questions but please some one help me?

Do you like both sexes?
Then you're bi.

There really is no being half bi or half gay... you either are or you aren't.
Can you go back and forth, yes. You can change your mind, you don't have to commit to a certain sexual orientation.

Hahaha. Tell the boy that you are not so easy girl who makes sex 5 minutes after one simple kiss, and tell also that if there is such a boy for who you would do this, he is certainly not that cute boy. He has to kiss you for it at least half a year if he wants sex with you, and even then it is not 100% sure, you will do with him. In your story there is nothing sign of that you would be bisexual. You will make sex with that person (boy or girl) who can turn you on effectively . But this does not mean that every boys or girls can turn you on. Only the exciting/attractive/appropriate/etc. persons will turn on you.

(V1)
This was never the way I planned
Not my intention
I got so brave, drink in hand
Lost my discretion

It's not what
I'm used to
Just want to try you on
I'm curious for you
Caught my attention

(CHORUS)
I kissed a girl and I liked it
The taste of her cherry chapstick
I kissed a girl just to try it
I hope my boyfriend don't mind it
It felt so wrong
It felt so right
Don't mean I'm in love tonight
I kissed a girl and I liked it
I liked it

(V2)
No I don't even know your name
It doesn't matter
You're my expiramental game
Just human nature

It's not what
Good girls do
Not how they should behave
My head gets
So confused
Hard to obey

(CHORUS)
I kissed a girl and I liked it
The taste of her cherry chapstick
I kissed a girl just to try it
I hope my boyfriend don't mind it
It felt so wrong
It felt so right
Don't mean I'm in love tonight
I kissed a girl and I liked it
I liked it

(BRIDGE)
Us girls we are so magical
Soft skin, red lips, so kissable
Hard to resist so touchable
Too good to deny it
Ain't no big deal, it's innocent

(CHORUS)
I kissed a girl and I liked it
The taste of her cherry chapstick
I kissed a girl just to try it
I hope my boyfriend don't mind it
It felt so wrong
It felt so right
Don't mean I'm in love tonight
I kissed a girl and I liked it
I liked it

lol sorry had to do that. but I am bi! I admit it. I like both guys and girls and im not ashamed. I kissed my bestie . now I know I am bi... so thik about it.

(V1)
This was never the way I planned
Not my intention
I got so brave, drink in hand
Lost my discretion

It's not what
I'm used to
Just want to try you on
I'm curious for you
Caught my attention

(CHORUS)
I kissed a girl and I liked it
The taste of her cherry chapstick
I kissed a girl just to try it
I hope my boyfriend don't mind it
It felt so wrong
It felt so right
Don't mean I'm in love tonight
I kissed a girl and I liked it
I liked it

(V2)
No I don't even know your name
It doesn't matter
You're my expiramental game
Just human nature

It's not what
Good girls do
Not how they should behave
My head gets
So confused
Hard to obey

(CHORUS)
I kissed a girl and I liked it
The taste of her cherry chapstick
I kissed a girl just to try it
I hope my boyfriend don't mind it
It felt so wrong
It felt so right
Don't mean I'm in love tonight
I kissed a girl and I liked it
I liked it

(BRIDGE)
Us girls we are so magical
Soft skin, red lips, so kissable
Hard to resist so touchable
Too good to deny it
Ain't no big deal, it's innocent

(CHORUS)
I kissed a girl and I liked it
The taste of her cherry chapstick
I kissed a girl just to try it
I hope my boyfriend don't mind it
It felt so wrong
It felt so right
Don't mean I'm in love tonight
I kissed a girl and I liked it
I liked it

lol sorry had to do that. but I am bi! I admit it. I like both guys and girls and im not ashamed. I kissed my bestie . now I know I am bi... so thik about it.

Go on with your life and forget it. You did the right thing. Good for you --