HI Dawn!
I can definitely understand that it is a bit difficult for you to talk to your mum, but you shouldn't worry! After all, she has been through it herself! I would recommend you find a quite moment when it is just the two of you and just go ahead and tell her!
In terms of which product to use, that depends on your body type and your flow. Why don't you try our on-line tool for finding the perfect product for you at http://www.always-info.co.uk/find_your_pad.html
You may also want to visit our teens site at www.beinggirl.co.uk, for more information about your period and the changes your body is going through!
Hope this helped!
Danai