@Glossy WIndows don't feel bad or anything about your situation. Believe me, you are not the first one to start their own business without realizing they've got the head in the sand, and I can guarantee you that you won't be the last either.
For your situation, I would highly encourage you seek professional help, as you will need one-on-one face-to-face help to cover your basis if you should be audited.Now I'm going to address some of your specifics below. But understand this does *not* negate my very *strong* recommendation that you get professional help.
I have no idea what my starting balance was
If you can't prove your opening balance, then as far as the IRS is concerned, its $0.00
when I first opened my business
What kind of business? This matters big time for tax purposes. A sole proprietorship? A single member LLC? A partnership? A multi-member LLC? An S-Corp? A C-Corp? Something else.
I used 5 different cards when buying things for my business
If you can't provide documentation to not only prove your purchase, but to prove it was for the business, then don't claim it as a business expense.
Sometimes, the money I made from my business would go into my personal checking account because My bills are automatically deducted from there.
If audited, and the amount of all deposites to all accounts with your name on them exceed the total income you report on your tax return, then you'll have a legal problem with the IRS for what they will see as unreported income.
The only thing I am aware of is how much I have made this year because I have receipt book with all of the income I've gained up until today.
Then without question, that will be the minimum amount you will enter on the "gross business income" line of whatever form you will report your business income on. (What form you use, depends on the type of business you have, as mentioned above.)
I know roughly how much in taxes I will owe at the end of the year.
Your rough estimate is probably way to low. Add at least 15.3% to that. When you are self-employed, in additional to "regular" income tax, the business will also pay an additional 15.3% self-employment tax. That's basically the employer side of your social security and Medicare taxes and it gets credited directly to your SS and Medicare account. So it's sort of like you're paying into your SS account for your future self.
What do I do now that I'm in this position?
First, admit to yourself (you don't have to admit to anyone else, as you don't answer to anyone but yourself) that you started this business with good intentions, but with no clue because you didn't do your homework first. (most likely because you had no clue of just exactly what that homework was... but it's okay.)
Second, seek professional help "NOW". Don't wait until tax time when it will be darn near impossible to get a one-on-one face-to-face appointment with a CPA or tax professional of any type. Come January, they're all gonna be booked up with 15 minute to 1 hour appointments, and that just flat out will not be enough time for you to learn anything.
Also, keep this in mind. I myself did not learn about taxes by doing everything "perfect" the first time. 99% of what I know is what *not* to do..... and I didn't learn it by not doing it. 🙂
