If you don't mind JT, I am going to deconstruct some things in your long post that I think you and others might find useful. As is always the case, this is just my opinion and not fact.
You will probably need a lot of support from your girlfriend. Have you talked through the reality of this?
The only counsel I will put on the table is this:
The fantasy of trading will burst very, very quickly once you start doing this. It is likely to coincide with a lump of money gone and your head in a bit of a mess. You will need support from your GF. If she is complicit in the fantasy then you will start to attack each other. If you have a strong relationship you will need her support to work through this and this will also take its toll on her too. You really need to look after each other. Both of you should be prepared for some fairly rocky sh1t ahead.
When Pat posted the
it was with really good reason. I think we're both saying the same thing to you - this is going to be far tougher than you anticipated on lots of different levels.