Your native language is the language that you first learn to speak as a child. In most cases, that will be the language spoken in the country or community where you live. If you are the child of parents living in a different language community from the one they grew up in, then you could in theory have a different native language from that spoken around you. (For instance, if you had, let's say, Hindi-speaking parents who moved to France, but still spoke Hindi at home, then strictly speaking your native language would be Hindi, because you learned it first. However, most children in this type of situation learn both languages more or less equally from the beginning, so then they have two native languages.
A native speaker is a person speaking the language with which they grew up, eg if you want to learn a new language it's usually better to practise with a native speaker.
A native speaker is a person speaking the language with which they grew up, eg if you want to learn a new language it's usually better to practise with a native speaker.