Let's start with the theme of the poem.
It's celebration, I mean who doesn't want it.
All of us can relate to this one as we all need celebration in our life.
Infact, most of us find little occasions in our life so that we can celebrate.
So I loved the theme as it is my favorite.
Mood of the poem is about happiness, enjoyment, sharing thoughts, cracking jokes, even making new friends.
This is what happens most of the times in the celebrations.
The imaginary you used are from visual to audible to olfactory to tactile.
Like in first stanza it is visual in these lines
Champagne is flowing, fast, bubbly and bright
Green patterned bunting, is hanging in sight
Along with the alliteration "flowing fast" and "bubbly bright."
In 2nd it is audible
Music is playing, the old stuff I think
Now they're all singing to Pink or the Link
In 3rd it is olfactory
Next there is food served, with scrummy nice smell
We've fallen under, the chefs magic spell
And tactile in fourth one
The largest piece, I just reach out and take
It melts in the mouth, then just disappears
And Like a meal is incomplete without a dessert. 5th stanza is that sweet course.
Saying to all the friends that let's not wait for happiness we can have it whenever we want.
Let's meet again, soon, and celebrate the gift called life as much as we can.
Because life is all about happiness and we feel happy when we are with our dear ones.
Milly, the rhyme scheme, aabb.
I always find it difficult to write in this scheme.
You did it with perfection.
All in all, a very good poem on the theme of celebration and the way you captured it with your words, I loved it.
I didn't find any flaws.