If you suspect that you have autism, but are not sure, you should make an appointment with your doctor and discuss your suspicions with them. They could help you find a health practitioner (probably psychologist/psychiatrist) who could assess you for autism. This process could take some time, as autism/ASD are relatively complicated to diagnose.
This said, I am also undiagnosed but suspicious that I have autism/ASD. I have felt this way for about 5-6 years, and might pursue a diagnosis later; however, due to the unsupportive nature of my family (who don't want to even consider this as a possibility), I will need to wait until I am an adult and independent.
I would suggest that you talk to your general practitioner as a starting point - they can probably direct you from there. Good luck! 
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Diagnosed: Autism Spectrum Disorder Level 1 without accompanying language impairment
I find it easiest to connect with people through the medium of fandoms, and enjoy the feeling of solidarity.
Too often, people say things they don't mean, and mean things they don't say.