Ok i started playing guitar a week ago and i was wondering how important it is that i should be alternate picking (down up down up etc).

For example when I play the intro to scotty doesnt know:


I can play it much faster and consistently if I don't worry about alternating, if i just use down strokes. But I'm unsure If this is a good habit to form. This may be a ridiculous question, but i certainly dont wanna hinder myself further down the road with bad habits?
always practice alternate picking the speed with that will develop naturally
im so used to alternate picking i just do it without even thinking
if you use just downstrokes you look like a noob
Get used to it. its easier to break these habits now while your just starting, then after you have been playing a year.
it is good to get your downpicking speed up but alternating can always be faster than just down picking. the faster you can go down the faster you can alternate. i find that scotty riff is a really good one for alternate and string skipping (begginer at least)

I started economy (alternative) picking a month after I first started playing and caught on really quick. If your having no fun at all playing, trying to alternate pick then maybe you should just down stroke a while until you gain some skill
There are plenty of "exercises" you can do to improve alternate picking speed. It comes with time. The main reason for it is because it can change the sound from high - low to low - high, or vice versa.