Well, I asked this girl out today. She was my dream girl in high school and now.. well I told myself I was going to try and be bold and hang out with people I was too scared to ask to hang out in high school. I do like her, she's pretty, and funny, I would really like to get to know her more.

Anyway, so I asked her out, over a social networking site, of course, not face to face or over the phone because I don't have her number. So she she said yes, with a smiley face and everything :D And we came up with things to do, and to me, it seemed like a pretty solid plan, (besides the date, place, and time, because when I asked her I asked what her plans were for next weekend) we were just going to get something to drink. I did not want to propose eating together just yet, as she is a vegetarian and I am not.

But she seemed like she was all for it, and happy about it, but then after we agreed on something to drink, she stopped messaging back. And I know, it's stupid to worry about it so soon, but I don't know what could have happened where she just didn't want to message back anymore. This was around 7PM and it's 3 in the morning now. Needless to say, we haven't set up a date or time, so I would think she would have to message back, right? She's not rude, and wouldn't just blow me off like that.

So what do you think? Am I being too paranoid and should wait it out, or did she indeed just change her mind and just doesn't want to say.

I am so excited about this date or "hang out" you have no clue, it has taken me a long time to get the nerve to ask her, and now that I finally did and she said yes, I am so happy, I can't even begin to explain. But like I said, should I wait it out, or assume she blew me off?

First - when you ask someone out, and she says OK, you suggest a day and time right then and there, as near to the present as possible. You're the one asking, so show some confidence! If she can't go then she will say so and maybe suggest another time, and you work it out.
Second, never ask someone what she is doing on a certain day and time. That's not really very polite as it puts her on the spot and it's intrusive anyway. Don't get all crushed about it; just avoid it in the future. You ask 'can you go on x day and time' - very different.
Wait until morning and suggest a time today!

Assuming anything anytime is a bad idea.
" should I wait it out, or assume she blew me off? "
You have another choice in addition to those two. Simply recontact her at a decent hour. There are many things that can disrupt electronic communications or she could have had an emergency.

Send her another message at a decent hour with a time. If she does not respond then you will have a better idea about her.

As a female I always found the endless "what do you want to do, when do you want to do it" messages to be, at best, aggravating. If you want to go out, yes, ask me for a specific day and time and place. You went back and forth for several hours? Makes little sense to me.

I was vegetarian for years. I went on dates with carnivores. I adjusted. She will, to.

I don't think she blew you off. I think she got tired of the indecisiveness. I'd say contact her again, don't reference this past correspondence, ask for her phone number - that will tell you if she's interested - and ask for a specific time and place. Her reaction will tell you what you need/want to know.

These IMs or PMs, whatever you want to call them on these social media sites are so impersonal, as is text messaging.

My take on this is that she just pacified you for the time being. Last night was Friday night. You didn't hear from her after 7. Most likely she had plans. You know that not all people stay on their computer 24/7, right?

You already sound needy and desperate. Back off before you lose her completely.

She may have just fallen asleep
She'll probably message back when she wakes up

Doodleman, you are 12 and have no business on adult boards.

I'm not sure you have any business on children/teen boards, based on your previous posts.