Is it worth to try to text in a couple of days and ask to go out?
The fact that she does not text me may show her interest level but I have a feeling that I need a stronger signal. So if she declines without suggesting better time or ignores my message than it is done.
I don't believe in hard rules, and what works for me may not work for others, but here is how I see it, based on thought and first-hand experience.
When you are asking a girl out, you are asking for compliance: Her to comply with your request to ask her out. If you walked up to a girl on the street and said, "Hey will you go out for a drink with me?" The answer 99.9% of the time is likely going to be no. Why? Because she doesn't know you and has not had the chance to evaluate you and determine if she is attracted to you or not. Yes she can appreciate your looks but for women, a man's looks are a less important part of the equation than a woman's looks are for a man. She wants to assess your value, ensure you aren't a weirdo, and see how you make her FEEL. She bases her decision on that.
If you are texting a girl and she simply doesn't respond, that's an indication of very low interest. So given that she has communicated this to you non-verbally, why would you then ask her for compliance (by asking her for a date)? She is least likely to say yes at this point, and it will likely further cement her low-value judgement of you based on the fact that you aren't acting socially calibrated. You should be put-off by her snub, not coming back around even harder.
@deBrito
I have tried the cute funny "Heard you flew to Asia and are climbing Everest" or <insert funny thing that is more custom-tailored to what you know about her here>, and while it does work to get the girl to re-engage about 80% of the time for me, it almost never leads to a date. Instead it just leads to more wasted time texting, and more snubs. They like the humor and teasing playfulness because they like attention and they like the feelings it gives them, but it's generally not enough to turn them around enough for them to agree to a date.
If you are worried you need to give her a stronger signal, then focus on interactions with future women - don't miss your opportunity to ask them out during a high-point in the banter. That's when to do it, not when the conversation is cold. It's simple: Banter, dig deep with your questions (below the surface level - don't interview them with many different questions about many different things - ask something general, then drill down to something specific like asking them WHY they do that thing or WHY they like it or HOW it makes them feel, then share something about yourself that relates to it). Once you sense her being warm, you ask for the date. Done. It's that simple.
Having said all this, a guy I respect once said, "You have nothing to lose by pinging value into the void. If nothing comes back, what have you lost? But don't go into it expecting you'll get anything back or you are likely to be let down." One last point, if I do ping a girl some days or weeks later after she didn't reply to me, I won't ask her a question. That too is a request for compliance. Instead, I will throw out something funny (like some of the examples above) or maybe send her a pic of something cool I'm doing with a comment like, "Awesome weather to be on top of this 6,000' mountain today!" But again, while this often gets a response, I can't recall it ever leading to sex. Usually just more flakiness..... more ignored texts later, a date that she flakes on, or a date that goes nowhere. But you can try and see how it works for you.