网民从开始上网至今的年数number of years one has used the Internet

• 尽管“网龄”不长，但我却与人民网有着不解之缘。

  Although I have not used the Internet for long, I am hooked on the People's Daily Online.

• 他18岁接触网络，至今已有10年网龄。

  He first started using the Internet at 18 and has now been using it for ten years.