well if i were you i wouldnt flower at 1.5 weeks as its too soon i recently had a thread on here askin if my plants were mature enough to flower after one week from germination as it says on the seedbanks info on the strain that i couldif ya get me.
i didnt really get a solid awnser so emailed the seed company they said that strain (cinnamon) can be flowered that early but reccomend to wait 2-3 weeks
anyway all ima say is that unless your seeds are a early maturing strain then i wouldnt flower yet you need to have around five nodes with secondry nodes comin off those otherwise you wont really get much off em if i were you i would wait another 2 weeks then flower if your tight on space
people generally say you should leave a plant for 4-8 weeks before fllowering as this is when they are mature enough to flower properly
see if you can put up some pics that will help us to see wether you should flower