Come on guys. Don't look back because everyone must have made the same mistake as you because they didn't dare to make the decision to invest in bitcoin. Moreover, at that time you weren't the only one who felt that Bitcoin was a Ponzi scheme, many thought that way because at that time finding Bitcoin information was not as easy as it is now.
What you need to keep in mind now is that it is never too late to become a millionaire by investing in Bitcoin. Do it now using the DCA method so that regrets like 2010 don't happen again in the next few years. Regret always comes at the end, so take advantage of your opportunities from now on to invest in bitcoin.
The question we are supposed to be asking OP is that how sure is he going to hold if he was to hold Bitcoin like others? He's such a type who didn't even see Bitcoin as a real valuable stuff, he will sell his Bitcoin once and for all the moment he see his Bitcoin grow into something. What about his financial status back then? Most people that we see holding Bitcoin for long term to date have some other stream of income and that was what stop them from selling their Bitcoin.
I'm not sure if OP do all kind of strategies to buy Bitcoin but I'm sure the opportunity loss will never be available again, perhaps from other coins but not from Bitcoin again unless if he is a wealthy person that is rich with some money to spare more like institutional investor. I don't know him and his current status but I'm not sure if he is that capable to do such kind of investment right now.