Your portrayal of shifting emotions from embarrassment to warmth, and then back to awkwardness, effectively conveys a complex character grappling with their feelings about Mrs. Nillimore. This nuanced approach reflects a realistic human experience, especially when discussing deeply personal memories with someone new, like a therapist. Your ability to navigate these transitions adds depth to your performance and engages the listener on an emotional level.

However, to enhance this further, focus on the gradual interplay between happiness and sadness. It's compelling that you don't immediately let go of the smile when sadness creeps back in—this subtlety in emotional transition is powerful. To refine this, allow the smile to linger in your voice slightly longer, even as sadness begins to overshadow it. This can illustrate the complex feelings one might have about pleasant memories that are tinged with the pain of loss.

Also, consider the pacing and tone as you navigate these emotions. Slowing down slightly during transitions between emotions can give your audience time to feel the weight of each moment. This pacing helps emphasize the shift from warmth to awkwardness, enhancing the listener's understanding and empathy for the character.

Keep exploring these emotional depths and using your voice to reflect the nuanced changes. This will not only improve the authenticity of your performance but also deepen the connection with your audience, making the narrative more impactful and resonant.