So if she wants to try something YOU don't like it's wrong? As others have said, stop labelling it and let her try what she wants.
Being "girly" or "princessy" doesn't suddenly turn you into some 1950's stereotype female who has to get married and stay at home and make martini's for her husband whilst laughing at what he says.
What is it with this "princess" crap anyway? Do we have to stick a fucking label on everything now?!! Sorry but ffs... believe it or not you can grow up liking shiny pretty sparkling things, wear make up and dresses but still rage against the machine and still want to try and put the world to right and treat everyone as equals.
It's not like she wants to try and juggle geese (very heavy and a bit bitey) or try sword swallowing!
Its not what she wears or how she looks, its how you bring them up and what you teach them.
I'm in my late 40's and my mum always told her 7 kids that we didn't have to follow the herd, we didn't have to get married or have kids or even have a partner if we didn't want to, she told us we could do what we wanted and to treat people how we wanted to be treated and we were just as good as the next person.
And guess what, my mum wore make up and dressed up to go to the shops but maybe that was her pride showing through as we were poor and her bit of lippy and mascara made her feel better about herself.
Yes I liked "girlie" things like dolls and LOVED my Sindy toys but I also helped my dad build a treehouse, was the official "DIY helper" to my 2 older brothers, went fishing (only female on the bank most times) and would actually wrestle my brother (overseen by my mum acting as referee) over who would play with the Action man tank or motorbike and sidecar. And as I got older I liked playing with make up and clothes to find my own "style" and never thought about "I need to get a boyfriend" because I had a ton of friends who were boys and I just wasn't interested for a LONG time all because of what my mum said to me.
It's not about you, it's about life experiences for your little one. Don't be so narrow minded and judgemental over things otherwise its going to come back and bite you on the bum.