Can you describe as "small"

a small spoonful and a small mouthful are both natural, everyday expressions.

If it is your baby, it's not natural to call him or her 'it'.

Is take the correct verb? Is there a better verb?
What is the difference between mouthful and spoonful and which would you use?
Is in proportion what is correct in the context?
spoonful is in proportion to the size of the spoon

Thank you

Is take the correct verb? Is there a better verb? 'Take' is fine. Or 'has'.

What is the difference between mouthful and spoonful mouths and spoons can be different sizes, but with a baby they are both small.
and which would you use? Either
Is in proportion what is correct in the context?

I changed the pronoun to 'she'. Could you tell me which should be used 'mouthful or spoonful'? Do you 'take' a spoonful or 'take' a mouthful'? Would you have said it exactly like this?

The baby always takes small spoonfuls/mouthfuls at first to make sure she likes the food.

Please can you tell me how would you write this grammatically?

She takes small spoonfuls the firs

I changed the pronoun to 'she'. Could you tell me which should be used 'mouthful or spoonful'? If she puts the spoon in her mouth herself, I'd say either. If not, I'd say 'mouthful'.
Do you 'take' a spoonful or 'take' a mouthful'? Yes

Would you have said it exactly like this? Yes