does my 15month old have autisim?

the purpose of this post has been the very slow development of my daughter. Physically she is still only crawling, she does walk around the furniture tho. her only words spoken are mummy and daddy. she also plays like a normal toddler.

my concerns apart from the lack of words and walking is her habbit of rocking back and forth in a trance while sitting in her high chair everytime, also she has an obsession with light switches ....... both of these concerns have been highlighted on many autisim websites.

i do know some children can be slow learners but my main concern is the rocking back and forth .... i do have an appointment booked with my doctor later in the week but would welcome other answers.