It is best to try to get your child assessed so if more support is needed you can begin the process. Go to your GP and then see what they suggest (though many may dismiss as "just as phase" but keep pushing).
My son has Dyspraxia and it took ages to get a diagnosis and then get him to have speech and language support and other support.
The earlier you start the more likely hood you will get in the "system".
We got passed from doctor to doctor and hospital to hospital and you have to learn a whole new "language" so it is best to start early.
One lady described it as booking a holiday to Italy but then landing in Holland. You are not ready for it, you don't know the language and so on.
Nothing WRONG with Holland but it is just not what you expected.
It MAY just be a phase but it is best to get it checked out.
Autism can cover a wide range of symptoms (it is called the "Autistic Spectrum") so not every child has the same symptoms.
More here
http://www.nhs.uk/Conditions/Autistic-spectrum-disorder/Pages/Introduction.aspx