Any profession worth having is going to take work. (ANYTHING worth having takes work, for that matter)
Always take an honest assessment of your abilities, strengths and weaknesses and then try to accentuate the positives and bring up the lagging areas. Easier said than done, I realize. Yet if you have a diligent work ethic you CAN and WILL succeed. Perhaps not top of your class, but far better than you would have had you just given up or not made a determined, concerted effort.
I'm just trying to say in a nutshell, give it hell for 4 years and see what happens. You have all to gain and zero to lose. Before you know it, years will pass and you just might get the title of Doctor.
Sound like a fair trade for your time and stick-to-it-tive-ness?
Does to me.