Read the following poem, "A Birthday" by Christina Rossetti and answer the question below.
My heart is like a singing bird Whose nest is a weathered shoot;
My heart is like an apple-tree
Whose boughs are bent with thick-set fruit;
My heart is like a rainbow shell That paddles in a halcyon [peaceful] sea;
My heart is gladder than all these
Because my love is come to me.
QUESTION: What mood do the details of the poem convey? (Look specifically at the three things the speaker compares her heart to.)