Tara Duncan
If you have to "relearn" something, what makes you think you learned and understood it in the first place? Discounting dying brain cells and loss of synaptic connections, if you assimilate a new concept you need to reinforce the concept by continuing to use it until it becomes like muscle memory. How many people learn to ride a bicycle and then forget how to do it?
If you internalize one concept you can connect it to the next one. Move at your own pace, and don't move on before you are ready. Most people learn nothing after about 25, so even small steps put you ahead of the proverbial game.