I've been dating this girl for about three weeks now (every weekend).
Last date (#3), she came to my house, and we made out.
The next day she implied we can cook together next time.

On the following weekend, on Friday, she asked me to come to her place,
but then she gave some excuses such as: She already had dinner,
she lives with her family, it's too late now and then she said let's
meet next time (I asked if we still on for tomorrow - no reply).
The next day, texted her good morning, said it was a good weather,
and if she wants to go to the beach, her reply was:
״I might go to Disneyland later at 11 so I might not be able to hang
out until later tonight or tomorrow".
I said: "Ok have fun!" and she replied the same.

Then I decided to wait for her to contact me first the
next day, but nothing. Usually I send her daily message
on the weekdays, but this time I kept waiting, but
no contact from her side (it's already been two days).

How should I proceed with her? Keep waiting
for her to contact me first, or should I send her
something?

Should have done more than make out.

Sounds like she had dinner with someone else, went to disneyland with him, hung out with him till later that night and met up again the next day.

Definitely no contact for now.

Well, she gave the impression like a geek innocent typical girl,
and even a virgin (that's what she answered on one of okc questions).
What is the point to call me over on Friday and then cancel?
I think she just didn't feel comfortable because of her parents.
Also she told me that she never been to Disneyland, so I
thought she went with her family. Am I too naive?

You achieved comfort, but lacked being more direct in the attraction when she gave you the signals. In short, you bore her and now you're showing excessive neediness and you're repelling her.

Ok, is it lost then? Should I stick with the strategy of not contacting her?

She is not the only girl left on the planet earth after the Zombie Apocalypse!

Hunt up some others, maybe re-open in a week or two.

Move the hell on in the meantime!

_________________
They call me the cat whisperer, cause I know exactly what the pussy needs.

Just dont contact her again and play hard to get , send women crazy!

In all honesty, I don't believe any case is ever lost. But if we continue to be honest you should simply learn from what you've gathered so you can grow and apply it in your future interactions.

Q:But don't I get experience from actually getting her?
A:Yes, even if you do manage to get her, you do learn something. But, face it, you don't need to get better in that aspect of the game. The fact that you're in this situation is an effect of you weakness in your BASICS of your game. ie you not being more direct when she showed you the signs.

Admit you caused this, not her.

Learn and move forward so that the next time you get it right. This is a PUA forum where we help each other move forward and improve ourselves. No real PUA will waste time, and most important be disrespectful towards your needs, by helping you with this girl before helping you with YOUR baiscs. This is the only way to learn.