There are so many reasons Here in this Forum, I will not give you Reasons,  I will Only Give you Advice.
Many have Doubted Bitcoin in the First Place When Bitcoin Was Introduced in the Internet Some of Them Really take Action and Eventually they are now the so called the millionaires.
 Do Some Researching because if you will just Only believe on the answers of your question without Trying to experience in investing in bitcoin then it will be  waste of time and Money,
 if you Will be able to experience then you will also be able to evaluate yourself.
Just Keep on trying So You Will not be dismayed after years and will not make reasons why you did not start Investing.