Should I dispose of my cheap bike or is it worthy to keep?
Depends on your definition of rubbish! If I were to guess it is probably all entry level components, unless they have been upgraded. That would be the first indicator. You can cross reference them by typing model numbers into Google. 

However, before throwing it away I would recommend putting it up for sale, or even better if there is someone in need, why not dust it off, polish it up and donate it to the less fortunate!