If you use the name and photo from your Google Account for your YouTube channel, you can update this information at any time. Please bear in mind that this will change your name and photo across Google services.
If you have turned on channel translations, your channel name may not be updated after you change it. When you change the name on your account, it will only be updated in your original language on YouTube. If you want your new name to be shown in all languages, please make sure that you update your translations too. You can turn off this feature if you want your name to be the same in every language.
Note: You can also use a different name on YouTube from your Google Account name.
Source: customised help