English Proficiency Question

On the Northeastern application, it asks how you can demonstrate English proficiency, and one of the options is “I am a native English speaker.” This might be a dumb question, but would I be considered a native English speaker if I learned English at age 4? Initially I thought the answer would be no (since it is not my first language), and some people agree with me, but others have been saying that being a native speaker is just speaking the language from early childhood, so now I’m just confused. Thanks in advance for your help.

Were you fluent in English as a child? Did you live in an English speaking environment?