First Grow, Just a few questions :)

Hi all,
This is my first grow. It's in a PC case (125w,2700k,CFL), it's an Auto Bubble Strain, it's currently at around 17 days old and is in Compost.
I was wondering if anyone could answer these?
What would be the most preferable way of keeping this thing small? I've looked at lst but it's stem seems quite thick now and I don't want to risk snapping it!
This should give you and idea of the space I've got.

Should I start my flower nutrients now I can see white hairs? I've heard starting them earlier brings on flowering quicker and keeps it smaller?

Also I noticed these marks on the lower leaves :S and the bottom leaves have a slight yellow to them :/? What could this be?

Cheers, any help will be much appreciated!

make a small scrog screen don't expect to much from this either way

Okay, yeah i'll be happy with just a small amount tbh Would I just fit it onto my plant already or wait till its abit bigger? cheers.

You can LST her. You may also need to do some supercropping down the line. Take a look at this cab grow I have. I had a light issue that I think caused stretch (not sure how long I had it before noticing). But this is 12-12 from seed. IN any case, I had to supercrop the hell out of her to fit the space.

whoa i see what you mean i'll give this supercrop a shot as it also says yeild is improved ! looks..erm.. kinda dangerous tho :L cheers for advice

Anyone tell me what's up with the leaves :s? or is that sort of thing normal ?