I honestly can't imagine how "only" could contribute to the sentence. What does it modify? If it's a last minute caution, I'd put it at the beginning.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
AvangiIf it's a last minute caution, I'd put it at the beginning.
PhilipMy advice is always to put the word only as close to what it modifies as possible.