Can I get decent at guitar in a short time if i practice a lot?

So I'm 13 and When i was 9 and 10 I played guitar. I guess I wasnt
that good but icould play some chords and stuff! So i want to pick up
the guitar again. i have been trying to learn some taylor swift songs
but when I try to strum it sounds terrible!!! My guitar is tuned, but
I just cant make it sound good. Then when I use my pick it sounds
like the plastic is rubbing against the strings (which they are but
still!)

So any tips you ahve are MORE than WELCOME! Thanks