Why is it taking a long time to charge my account after I buy music?

Hello Samara

There is nothing wrong.

It's a policy.

Check out this link :

How iTunes Store purchases are billed - Apple Support

There are two reasons: credit card fees and consumer psychology

Most credit card processors charge their customers (e.g. Apple) a per-transaction or monthly fee, and a percentage of the purchase.To save on fees, Apple often groups transactions together. Apple knows that if you've bought one thing, you're likely to buy another—often pretty soon after. So, Apple waits to bill your card for a day or two in case you make more purchases that it can group together. It's cheaper and more efficient to bill you once for buying 10 items than to bill you 10 times for 10 individual purchases.

You can see how Apple groups your purchases together in iTunes by doing this:

1. Open iTunes on a computer.
2. Click the Account menu.
3. Click View My Account.
4. Log into https://appleid.apple.com/
5. Scroll down to Purchase History and click See All.
6. Click the arrow next to an order to see its contents. You may not have purchased these items at the same time, but they're grouped together here as if you did.