I have 2 plants 1week apart,the younger one is 13&...

They will nearly double in size.. if that's too much you better go to 12-12 immediately. If that's the case, maybe top the most dominant vertical shoots back to ~even and in the ~3+weeks of growth left after 12-12 switch those sites topped have plenty of time to grow in and be useful. i'd only do this if very concerned. it could reduce yield a bit, but could also avoid running out of space.. which would improve your yield immensely, lol.. i know sounds conflicting. 2 weeks should be plenty to heal, but do inspect it a bit. you can try HST too.. bend it down horizontal where it is too tall. tape up the stem where it snaps a bit.