I for one hope you prove your doubters wrong and make it. Every great thing a single man has ever achieved started off as a stupid idea that everybody wrote off as ridiculous.

On the other hand, you're talking about playing a bloody card game instead of doing cool things with your engineering degree. If you feel underchallenged with your job prospects, it might be worth considering aiming higher, like starting your own business in the field of your expertise. Don't start thinking that you a choice between "a normal boring job" and an "exciting life as a pro poker player". Perhaps it will be the most rewarding for you for you to choose an exciting, challenging life that takes advantage of everything that you've worked for all your life, instead of starting something from scratch. Don't lose that drive though! Dream big, but dream super smart too, is what I'm trying to say.