I play guitar. Well, I haven't played in a while, but I was in a band a few years ago. I'm one of the few that found the transition from guitar to bass difficult. I have small hands, but that shouldn't matter, I just couldn't get it. Best advice I can give you is to be patient. Sounds stupid I know, but you wait. You're going to want to throw that bass across the room in no time.
What style were you looking to get into? I don't know much about bass, but most guitar centers have guys that can direct you in the right direction as to a video or a good book. The best way is live lessons or having a friend to teach you. I never had a teacher for guitar. I had friends show me some things, but for the most part taught myself. You learn some bad habits that way. Stick to your lessons and learn the notes. I don't know notes, I just play, and it bothers other players sometimes when they ask you to play a note and you ignorantly ask them what chord that is.
A bassist I used to play with told me he learned from a really cheesy video. The guy on the video just showed him what to play and played along with him and eventually, after watching it about 100 times, he said he learned enough to get some confidence. Like I said, patience.
You have to have strong fingers with either guitar or bass, but especially with bass. Get one of those finger-strengtheners (whatever they call them). I have one that has the individual points for the fingers and that will help you strengthen your fingers and hand.
Ultimately it's all about comfort. You'll feel very awkward for a while, but eventually it'll feel right.
It's a fun instrument, but realize your role if you join a band. We had a few guys who basically wanted to put in bass solos in every song and it doesn't work that way with most bands. Every member has his role in a band.