Overall - extremely heartwarming. Love them being sweet and adorable.
The part where they got engaged is unhinged . Like, her initial responses were very good! And, if their feelings are true and enduring, it doesn't matter if they get engaged at 10 or 39. IMO it'd be way more romantic for him to respond with something like - I'll put all your doubts to rest by being an absolute real one for the next 8 years. But I guess that level of emotional intelligence is a lot to ask for from a prepubescent boy?? Whom they allowed to make a lifetime commitment??