I took the data structures class three times before i passed it, true story. By the end of my computer career, somebody actually disparaged me by saying i was a natural at computers, that somehow what i did didnt count because it was so easy for me.
Really, once you figure out the secret behind data structures - that you are looking at the address OF the address?! - something like that, or the address of a list of addresses, not the actual data - and read some of the old James Martin books, and how to write a perfectly structured program, and IT SHOULD LOOK BEAUTIFUL - then you will be on your way. Also read malcolm goodwins book on Masters - it will take you 10,000 hours to become a master at your work. Which is more or less the olden times journeymans apprenticeship.