from a balance stand piont i'd say fine enlarge preson is not that great and your ally blows a turn casting it.
from a rules stand piont it should be a no brainer it say right in the reading you are a humanoid and there for able to be effected by spells that target that type
If the DM "house rules" you are an Animal by type - Animal Growth is necessary instead. It would seem inappropraiate however, as YOU have an intelligence above 2.
If the DM house rules you are a "Magical Beast" - I would have to check the spell.