I'm not sure what you're seeing is an effect of being older. Learning the first 200 kanji in RTK is easy. So easy it feels like magic.
Things get much, much harder by the time you get to 1000. You start to have very similar overlapping words (e.g. Earnings and Profit and Assets and Savings), primitives that share the same name as an graphically-unrelated kanji, kanji that are made up of a grab bag of completely random primities, e.g. Dissolve, which is made of ceiling, mouth, hood, human legs, spike, insect.
I'm also skeptical of the idea of learning these things permanently on your first try, as Heisig claims. He even used flashcards himself, and describes how to review with them properly. There are certainly some characters that I have such vivid stories for that they stick easily, but coming up with 20 such vivid stories per day seems impossible.
Things get much, much harder by the time you get to 1000. You start to have very similar overlapping words (e.g. Earnings and Profit and Assets and Savings), primitives that share the same name as an graphically-unrelated kanji, kanji that are made up of a grab bag of completely random primities, e.g. Dissolve, which is made of ceiling, mouth, hood, human legs, spike, insect.
I'm also skeptical of the idea of learning these things permanently on your first try, as Heisig claims. He even used flashcards himself, and describes how to review with them properly. There are certainly some characters that I have such vivid stories for that they stick easily, but coming up with 20 such vivid stories per day seems impossible.