I was so excited the day I bought my first professional grade steel string acoustic guitar. I was a 16 year old fingerpicking folksinger, and had been playing on a nylon string classical model. I'd practiced for two years with the fire of nonstop musical inspiration, conscientiously saved money in a new guitar fund, and now it was finally time to upgrade my instrument.
I questioned other musicians and read the guitar geek magazines for information on acoustic guitars. Martin Dreadnought body guitars were hot at that time. The D-28 and D-35's big wide Brazilian Rosewood bodies supported a huge and beautifully balanced sound. The booming bass end and warmly bright treble strings blended evenly with a solid mid range. Nice and loud, too! Great teenage angst response in a guitar!
I bought a brand new Martin D35 and though it was large and difficult to handle, I persevered and managed to play that guitar "pretty good for a girl!"
Years later I realized what many frustrated guitarist wannabes never learn-- My beautiful dreadnought guitar was too big for my 5 foot small body. I had experienced more physical pain and technical frustration and was working harder than the average sized guitar picker did while playing on the same kind of guitar.
Most guitar builders, salespeople and pickers were and still are men who are larger than me. It didn't occur to anyone to advise me that smaller people need instruments that fit their hands and bodies just like the smaller shoes on their feet!
I'm sorry to say that 30 years later, things haven't evolved much in the guitar sizing department. I still see smaller than average female and male guitar students come to their first lesson with huge unplayable instruments, and it's my sorry job to tell them their guitar is wrong for them.
Most beginning music students are clueless when they rent or buy their first instrument, and must trust a salesperson's knowledge and judgment to help them choose an appropriate and playable instrument. It is a rare merchant who pays attention to instrument sizing, and if you are female, you probably have few role models to help with this issue.
Pay attention to how the instrument feels when you hold it. If your first impression is that it is too big, then look for a smaller scale instrument. Bigger and louder is not necessarily better, and you will learn to play with more facility and less tension and technical frustration if the size is right!

With a Smaller Guitar and Better Technique,
Queenee