I asked a question and got some vote downs now I know that I was wrong I wanna delete it, Will I get my rep back?
Yes, your reputation will be restored. If not immediately, then at least within a few minutes.
However, you should pay attention to the following: every down vote and every closed question has an impact on your account. Deleted questions are also factored in. If you have too many downvoted and closed/deleted questions, you may be automatically blocked from asking.
Currently, your account is in a good standing, but please always keep the possibility in mind before asking a new question. Is your question reasonably scoped, on topic, and objectively answerable? Then go ahead and post it. If not, maybe you want to do a little more research before posting, or chat with others.
If there is any possibility to rephrase a question in such a way that it complies with our scope, or if you can add details to make the question answerable, then you should absolutely do that instead, rather than taking the "easy" way out. This, of course, is only possible when the question isn't absolutely off topic or not even based on a real problem. Those are often harder to rephrase.