How do you interpret Frankenstein's initial response to the success of his experiment?
In Volume 1, Chapter 5 of Frankenstein: Or, The Modern Prometheus, Victor is only concerned about his work and how it might, if successful, live on.
It was on a dreary night of November that I beheld the accomplishment of my toils.
Victor only wants to get published: he values his journal over his creation. All his passion and preparation were put into the act of creation, not taking care of the thing created. He is a rogue scientist, not a nurturing father.
Notice the "my": he takes a completely subjective and selfish view of the process of creation, regardless of the consequences. He sees the act of creating life (or reanimating life) as a science experiment, not an existential birth. The whole process seems like a grand dare: he wants to see if he can do it. In this way he is irresponsible both as a scientist and as a father.
The creation is immediately anticlimactic for Victor. After the creature opens its eye, his work is done as far he is concerned. He abandons and tries to abort his work.
...by the glimmer of the half-extinguished light, I saw the dull yellow eye of the creature open; it breathed hard, and a convulsive motion agitated its limbs.
How can I describe my emotions at this catastrophe, or how delineate the wretch whom with such infinite pains and care I had endeavoured to form? His limbs were in proportion, and I had selected his features as beautiful. Beautiful! Great God! His yellow skin scarcely covered the work of muscles and arteries beneath; his hair was of a lustrous black, and flowing; his teeth of a pearly whiteness; but these luxuriances only formed a more horrid contrast with his watery eyes, that seemed almost of the same colour as the dun-white sockets in which they were set, his shrivelled complexion and straight black lips.
Enotes says it best:
[Victor] finds the creature repulsive, with “yellow skin” stretched tightly over its muscles and arteries, a horrible grin, and watery eyes. After working for nearly two years, on what he thought would be a beautiful creation, Victor realizes “the beauty of the dream vanished, and breathless horror and disgust filled my heart.” Unable to bear the sight of his creature, Victor rushes from the room and collapses, exhausted from the shock. The creature comes to his room and tries to speak to him, but Victor runs out of his house, desperate to get away from the “thing” he has created.