Get it in soil now. Now that it has germinated, any longer on paper is wasted time. I germinate my seeds on paper towels and I just plant all my seeds of one variety as soon as I see a radicle emerge in one of the seeds. The longer the root grows on paper, the more chance of damage when you remove it or plant it. Also, it seems like seeds are more susceptible to fungal attack when in the overly-moist environment of germ paper. Helmet head seems to be more common when seeds grow too long out of soil, too.