No worries, one nice thing is when you are advancing from your basic course to Advanced, you can change agencies. That is nice as you are not locked into one agency, plus you can get an opportunity to check out the differences 1st hand. No restrictions or extra charges either!
And even if you do decide to go for a SCUBA job, your first few classes still don't matter. So go with whatever shop, agency, or instructor you feel most comfortable with as that is the top priority....well second to getting certified! You are in for an amazing adventure, glad to see another diver in the making!