Any good guitar players here??

How long do u think it will take a person to learn how to play good classical guitar??
I'm kinda starting from scratch.

There are quite a few factors you need to think about for this situation. I'm assuming you're already a guitar player. Do you read music? If not, it make take some time to sit down and learn everything. Do you have an instructor for classical guitar? This is important, as there are many different things you'll need to adjust, such as hand position, posture, etc.

Aside from that is general musicality in your playing - do you just play the notes, or are you able to place some stylistic integrity into the piece you're playing. Each musical period uses different stylistic characteristics, so you'll have to do a bit of research on what each piece you play is supposed to sound like.

That being said, if you have a good instructor, within a couple years, you should be able to play some fairly nice pieces. I would pick up the Carcassi classical guitar method book. It's pretty amazing, and it takes you from the very basics to some pretty in-depth playing. Giuliani studies are always good to have, and alot of them aren't so difficult. There are tons of different methods out there. I'd get an instructor if I were you, and they should be able to tell you what will put you on the right path.

I reckon on putting at least a years hard work in for the fundamentals, and the rest of your life for developing your skill, your playing and your ear.

Assuming you can play guitar already - a good solid two years hard work.

If you can not play guitar already, than only one year.

You must practise regularly...every day. At least one hour per day but two is better.
Break it up into two sessions ; one hour in the morning and one hour in the evening. I strongly advise you to get a teacher and have lessons for classical guitar ; at least for the first 12 months.
You should be quite a decent player after about 5 years.