La glace is a direct object (complément objet direct, COD) of the verb aimer. So the pronoun would be le (m), la (f) or les(pl), and place before the verb.
La glace is feminine, so we choose la as the pronoun.
In answering, we place the pronoun after tu and before the verb, making it
"Oui, je l'aime." (not forgetting the contraction of la to l' when verb begins with a vowel)
