can I learn ethical hacking by self
Dear Aspirant,
No, you can not learn ethical hacking by yourself. At least not without learning about the basics of the computer programming, networks and many other important aspects of the functionality of the computer software and the hardware.
You need a structural preparation first to get started with the ethical hacking. You can for example start a professional course in the computer science and once you are done with the basics of the computer which might take 2 years or more, you can start with ethical hacking.
Hope this helps. Thank you.