I am a mummy who just turn 40 this year and my work contract just ended. Is it true that at this age difficult to find a new job especially something that you like and higher pay ?

Guess it also depends on your area of interest, the current job market situation, your expectations etc. Experience counts, but if the there is limited supply of positions, the starting pay will likely be affected. Never try never know. If you can afford the time, take it as a short break and look around to find something that you would enjoy. It is likely that you would not want to be switching jobs halfway given your other commitments (family for example). :)