Welcome to TFF Bram!
I'm Trixsie, nice to meet you *curtsies*
Feel free to look around and explore and make friends
There is a HUGE love of arts and crafts in the fandom so I'm sure you will find some kindred spirits.
As for telling your parents, firstly for going on a train, I guess your parents will already have an expectation of whether you would tell them about your train related adventures and I trust you know them best. I would certainly be happy for my cubs to travel by themselves but I would still appreciate being kept in the loop.
When it comes to telling them about joining the Forum, I think the main thing is that you just be open. We try to maintain a family friendly site so there's nothing terrible here and they are welcome to visit as guests to reassure themselves. Treating it like something secret or forbidden will only make it seem weird when they do find out.
But that's just my opinion
Now if you have any questions feel free to ask here or PM me!
And don't forget... HAVE FUN!