Aspirin Intermediate Reaction Help

The first thing that occurs is protonation (Correct, protonating the anhydride is an important step to make sure that the alcohol group is nucleophillic enough for the reaction to proceed well), as the hydrogen ion dissociated from the acid and attaches itself to an oxygen from the acetic anhydride (You don't need to say this part. Technically, the acid is already dissociated as it is in a solution of water, and at A-Level the expectation is that you understand acids like sulfuric or phosphoric acid are strong acids-fully dissociated in water. While the main solvent here isn't water, mixing up those ideas doesn't convey the clarity you probably should be trying to convey. Also, saying that it attaches itself to an oxygen opens yourself to questions like- why does it attach itself to that specific oxygen? Is answering those questions within the scope of what you're doing? If not, best leave it out). A positive charge on the molecule allows for the salicylic acid to react with the anhydride (it does, can you explain why?), creating a resonance structure (what is its name, and what exactly do these three arrows mean?) (A resonance structure is a different way of drawing a molecule that has some degree of delocalisation. Basically, you can draw the molecule with an oxygen with three bonds and a positive charge, or you can draw it with the carbon having three bonds and a positive charge. It can be represented two ways. This shows that the delocalised electrons are delocalised over several atoms, and that's important because it tells you where the electron density can be expected to be highest. This helps you predict where nucleophiles like the alcohol group will want to react). Then, the molecule dissociates (an intermolecular rearrangement), forming acetylsacilylic acid and acetic acid, and the hydrogen ion returns back to the catalyst (just say- regeneration of the catalyst).

Thank you for your insightful answer!

I am supposed to talk about its attachment to the oxygen, as my teacher wants me to be quite detailed about the process. Would saying it attaches to the oxygen because of the free electron pairs be correct (and the fact that oxygen is more electronegative than all the other elements present? Or would that fact not affect it at all, since it's essentially a proton that is attached...).

The positive charge causes the molecule arrange in a way that a bond between the two reactants can be formed, as the electrons become delocalised (this is my understanding from what I've read online... is my thought process correct?).

The oxygen becomes positively charged, and is therefore neutralised by the hydroxyl group - as a result, the C-O bond in anhydride breaks and the hydrogen dissociates itself from the aspirin (I am not quite sure as to why the C-O bond breaks, though...).

Was my further explanation correct? I read up more online as I want to fill in my gaps.
Thank you again for your time!