If you registered the business in "active" status with your state as an LLC (single or multi-member LLC, it doesn't matter) you are considered to be "open for business" on the date you told the state it was "active". Unless there are some extenuating circumstances (and I can't think of any unless you're a convicted felon for violating tax laws in the past) it's fairly safe to assume your 2553 will be approved.
When did you send the IRS the 2553? I would fully expect you to have a response within 60 days; 90 at the most.
