Hello Bartbara, I'm Keith and happy to help you with your question.
You do not get Child Tax Credit if your income is over 40K.
The year would appear to be an irrelevant for your on line data entry as you are way over the maximum. You should just enter 'Yes.'
Don't worry about a self assessment form. It is not due until the end of the tax year and in any event it is your responsibility to self assess if you have significant un-taxed income or adjustments even if HMRC don't send you a form. Don't get yourself into a fret, you are in the very early stages of any problem and most are easily and amicably resolved.
Try using HMRC web site 'High Income Child Benefit Charge.' Any search engine will find it. It gives the links to a variety of calculations.
Thank you for your answer but I am still confused.
I do not receive child tax credit. I am, I believe entitled to receive child benefit if I earn less than £50,000. The government changed its legislation in January 2013 so that if you earn £50,000 or more you may still claim child benefit but also need to fill in a self assessment form. What I need to know is if I was earning less than £50,000 during the tax year ending 2013 do I need to fill in the form?