Start learning Hebrew.....

[Nachshon]

If I may interject, I am a big fan of English-speakers first learning modern Hebrew, before going on to Biblical. Modern Hebrew is more Western, and so easier to grasp, when you're going from English. It allows you to get basic ideas of grammer and pronunciation, while building a good vocabulary, to then help you be able to move on to the more complicated Biblical Hebrew.

Just my humble opinion.

Shalom,
David

[R' Y'hoshua Moshe]

It can be helpful. Much of the "modern" conversational Hebrew that you will learn will help you with learning Biblical Hebrew. Much of it is similar or the same. I think learning both at the same time is something to also think about.

Shalom,

Reuel