Do not waste your time or money going for Medical Assisting if you want to eventually be a nurse. The market is over saturated with way too many for-profit schools cranking out MA grads. Many areas of the country are difficult to find employment as an MA.
And in most places, none of the MA courses satisfy any requirements for nursing school. They will not transfer or make things any easier for you.
If you're scared of tackling RN school, go for the LPN which is about a 12-15 month program. But beware that your job opportunities might be limited. In some places not as many hospitals use LPNs and they are limited to out patient clinics and nursing homes.
If you find a good employer they will pay tuition reimbursement for you to go on and earn your RN, which would be about another 12-15 months in a LPN to RN bridge program.
The RN program is challenging no matter which way you do it, but it's not the content of the program that is hard in and of itself, it is the amount of work, the quantity of the content that you have to learn in such a short time span that puts pressure on people. It's not uncommon to have to read 10 chapters in a week for one class. You need to learn to become an effective studier, hit the highlights first, use your instructors' notes, ask questions if you don't understand. You can get through if you put in the effort, it doesn't take a genius to get through nursing school, just a hard worker.