I think anything is possible with hard work and dedication.
DIT is for review and Dr Conrad Fischer famously said "You can't review what you never knew".
Also, DIT basically reads First Aid to you with few extras.
I, therefore, suggest a course which starts from the bottom up.
I would recommend Becker eCoach followed by Dr Raymon's integrated cases.
But don't take my word for it and find out yourself if it suits your learning style by attending few of their webinars for free.
http://www.becker.com/usmle/resources/usmle-events
Full disclosure:
1. I have not taken Step 1 yet.
2. I have not used DIT but my impression is based on the feedback on SDN . You can decide for yourself by watching their
sample videos on you tube.
3. I am not affiliated with Becker and my recommendations are solely based on the information gathered while attending their free webinars.