Hello PUA'sI'm gaming this particular girl (currently day 4), who told me she wanted to take things slow (Learning to calibrate) and everything is going 'ok'; she shows interest, she's investing but she is stuck in the 'I barely know you' shit.

So today I went out with here and there were other guys and girls in the venue, some girls playing with a football. So I noticed she was getting anxious and I told her that we should get up and play a little bit, made her stand up played a minute or two and she goes to my ex-friend's house and brings him and they start talking.

I noticed she was giving IOI's and he was going along, so I decide to stop playing and game them both; introduce myself, start talking about stupid things with guy making the attention slip out of his hands, locked the girl in and returned to conversation with girl (a close one in my opinion). Time goes by and we have to live so I say goodbye to her bff and suggest her we should go out some time (the 3 of us), meanwhile girl goes say goodbye to others and gets clinged on to ex-friend (really long hugs + hand holding = not good), closing with her bff took 5 sec more than I expected so she kinda ran away of the place and I had to go behind her, I acted as nothing was wrong and say goodbye (noticed I didn't get the same 'goodbye' as ex-friend).

So she knows the guy for a lot longer than she knows me, which makes sense in her mind(previous investment), and she obviously has feelings for him.
She is interested in me but, because of the time we've known each other, she doesn't let herself enter in comfort and might actually think of me as her 2nd option.

Should I leave her because of her feelings towards the guy? How should I show I'm the prize not the 2nd place?
Should I get some effort in gaming her bff as leverage?

Forgive my noobness if this is a no-brainer for you.

Sorry for the spelling, crappy keyboard is set to spanish (Spanish native language for me)

It does not sound like she in nearly as interested or invested in you as you think she is...

Obviously I'm only going by what you wrote here, but you don't even sound secondary here, to me... She wants the other guy and you're in the way.

Not trying to be harsh, man. Just saying what I see.

if that's the case, what should I do? Should I proceed gaming her or just leave the things as they are?

You'd be gaming a disinterested girl.

Guess you are right, I'll move on to the next one then. Thanks