My one page website has too long menu (many items). I want to remove one of the items - named as "services" and stay only with "about" item instead. Is it OK to remove this item from menu? Sorry, if the question is worthless.
What you should rather do is reconsider the fact that you use a onepager. You should never alter the content just in order to fit it into your system, but your system should evolve in order to handle your content.
Therefore, if you have too much content to easily fill a onepager and it is exploding your menu space, you shouldn't use a onepager.
If you insist on using a onepager, maybe use a different kind of menu in order to fit your needs.
Some links for your research:
Probably you should start exploring few things at your end first, Such as
What am I creating? & What value it Provides?
If you are creating a webpage which serves the purpose of showing information about ones particular services and about the brand/company then there is no point choosing either one between the two. Instead you should probably re-think about your design strategy and should not think about altering the menus.
And more over As @marvinpoo rightly said "You should never alter the content just in order to fit it into your system, but your system should evolve in order to handle your content."
If you want to give your navigation design another try, then probably you should give a look at it. https://www.butterfly.com.au/blog/design/10-steps-for-better-website-navigation
depends on what your users need:
If they need 'services' you have to keep it.
And as the poster above said, you may have to redesign your navigation menu.
The fact that it is one page long means you have too many items surfaced at the top level. You may get away with organising the less important items under other items or on other pages, but like I say, do research to tell you a good arrangement.