First of all a big congrats to you! So, is there a current PTA board at your daughter's school? Then there should be an election this spring to elect officers for the next school year. This board should be able to give you access to their records, including the financial information you need. Current bank balance, bank records, etc. Check with your district PTA to see what the deal is regarding those meetings. The current bylaws should be posted on the PTAs website, or, if that isn't the case, the outgoing offiicers should have a copy. Your first steps should be to meet with the outgoing team, along with your fellow new officers and talk about what is ongoing, what the expectations are for next year, etc. Then, spend some time with your fellow officers to talk about (big picture) you are hoping to do next year. Your next step should be a meeting with the principal to see how to best work together. Then it will be time to identify what needs to be done during the summer -- there may be some back to school program planning that needs to take place.
But, relax, you have plenty of time. Do one thing at a time and it will come together.
In the meantime, check out of these articles on leadership. These should be helpful in giving you the sense of how you personally want to approach this job.
You're elected, now what?
17 Dos and Dont's for Presidents
Find Your Leadership Style
The Leadership Skills that Matter
All the best!