Hi Helena,
Welcome to our little corner of the Internet. I hop that you will find the help and encouragement that you want.
Reading your story so far took me back to when I was in my early twenties, when I felt and thought many of the feelings and thoughts that you are describing.
Helen and Nikki have already given you very sound advice. Let me add some things from my experience,
  • I understand that you want to do some investigation / experimentation before revealing anything to your girlfriend. I presume that your reasoning is that there's no point introducing this 'big issue' into your relationship, with all the risks that entails, if its only 'a passing fancy'. To that, i would reply that it doesn't sound like a passing fancy and that the longer you delay in telling your girlfriend the bigger an issue it will be.
  • I don't know where in Europe you are but... find someone who does makeovers for crossdressers and treat yourself to a makeover - not merely for an hour but for 2 or 3 hours if you can afford it. There is nothing to compare with the experience of seeing yourself as a girl for the first time!
  • Sorry to be personal but... lose some weight! I'm around the 110 kg mark myself but I'm also 6' 1", and i need to lose 10 kg minimum. You're several inches shorter than me (which makes wearing high heels less of an issue - lucky you). Do it now while you're young and active and its relatively easy. There's nothing wrong with being a 'big girl' but drop down a couple of sizes and you'll have a better range of clothes (there's the necessary motivation!).


Good luck and keep us posted!
Judith xx