When we are young, we usually operate in very simple terms. The concepts that we can fully process are few and simple, because the range of our experiences is very limited. However, as we grow older, we are able to comprehend and understand a lot more ideas. We are also able to use more difficult language. This makes it possible for us to understand more complex concepts.
Realised needs to be changed from the past tense to the present tense so that it is realise. In this case, the verb is part of a prepositional phrase and is being used to talk about moment within a story set in the past.
Have forgotten needs to be changed to had forgotten since it is a past action that happened before another action in the past.
Bought and got need to be changed to buy and get so that the sentence is parallel. These words are part of a series of actions that starts with the wake.
