Hello,
DD had her first period aged 10 in early February. She has not yet had her second. Is it usual to have such a long gap at the beginning? Pretty much 28 days after the first one started she had spots and sore boobs, but no period appeared. Still nothing 45 days from the first one starting.
I keep telling her not to worry, but she is. Puberty for me was so far back in the mists of time I can't remember my own experiences! 
Thanks very much.