Wow, do we have a lot in common. I, too am a new president and have written the by-laws, scheduled our 1st meeting in 5 years and am petitioning members(anyone who wants to) please volunteer to help me. I need a PTO board! I have a really wonderful principal who has been running the money by himself, I was welcome to get things going. The treasurer was relieved.
We have though, already encountered the same kind of person who I will say is a "go-getter". She can really get people moving. She can raise money fast and pulls some weight. Have you spoken to this person about how you feel? Not how others perceive her, but how she makes you feel? Like excluded, alienated, frustrated, unworthy, unuseful. These sound like good words to describe how she makes others feel. And your feelings, as a reminder, are not ever wrong. They are valid. Because you two have to work together, she needs to validate you. I suggest telling her how you feel, (remember not what others think or how they talk) but how she inhibits you from being a part of the plan. How she alienates you to the side lines. How she gets all the glory. She will need to hear it honestly. Your integrity as a leader is at stake. I did this today with my member and we were finally on the same page. Not that I like her any better, but now I will not tip toe around her feelings. It's really hard, but if you're stressed, it has to be done. You and her will probably find you will work together fine if you can be honest---even honest about how she needs to let others in on the plans.
Just some thoughts for you. Don't give up.