How did I get in Gravity Falls?

Run

---------- Amanda's POV-------

I didn't think, I just ran. I didn't know where I was going, but I knew I was getting far away from here. I was almost to the front door of the Mystery shack, I WAS GONNA MAKE IT!!! I smiled and ran faster. I touched the doors handle, I pushed. Nothing, I pulled... nothing. Then reality struck me. The door was locked, I tried all the others. Locked.

I was trapped, I ran around in circles, trying each door several times.

"Ha! I told you locking the doors was a good idea!" I heard dipper yell. Ahh crap.

"Look, we don't wanna hurt you. We wanna help." Mabel said sincerely.

I sighed, I can't keep running forever.
"Okay. But, we might have to go upstairs to the attic." I whispered to them. I followed them to the attic. Once we were there I began explaining.

"Okay, I don't exactly know what I'm doing here but there is one thing I do know. I'm not supposed to be here." I explained. Dipper and Mabel looked at me and then each other then back at me. Then I continued.

"I just woke up in the woods and then dipper here tackled me." I stated, pointing an accusing finger at Dipper. He gave me a confused look that quickly turned into a suspicious one.

"Wait a second... I never told you my name." He said, glaring at me.

"I know. It's weird, I know everything about you two, but only basic knowledge about myself." I explained. They both gave me confused looks. I sighed and continued to explain.

"My name is Amanda, my favorite color is teal, and I well... That's it." I wondered why I didn't remember everything...

"That's it? Nothing else?" Mabel questioned.

"Umm, OH! I'm 13 years old! I remember that!" I remembered something else YAY!

"Is there anything else?" Dipper asked.

"About me? No. But somehow I know everything about you guys." I said.

"If that's true, then tell me about myself." Mabel said.

"Well, your name is Mabel Pines, you have a pet pig named Waddles, your nemesis is named Pacifica, and your first kiss was with a merman named Mermondo. Also there is this creepy chubby guy named Gideon who is like, obsessed with you." I listed off some things. Her mouth was wide open.

"Okay, all of those are true but, uhh, what about dipper?!" She asked again, uneasiness settling in her voice.

I sighed. "Well, his name is obviously Dipper pines, he has a secret birth mark of the Little Dipper under his hat. He has a "secret" crush on Wendy, the cash register girl. He is obsessed with Journal #3. And lastly he has made a deal with Bill cipher, where Bill stole his body in order to destroy the journal." I wrapped it up. Wait... But who's this Bill guy... All I know about him is his name, and that he made a deal with Dipper......
I'm going to have to investigate on this "Bill Cipher" guy...