Need to bring inside?

I know this will probably sound noobish..but I always had my plants start and end at the same time. Anyways, started a plant outside in June from seed. It is only 20 inches tall. The other plants I had outside from may till now are flowering. Since they are flowering already I was worried about the other one going into early flower. Should I bring the smaller plant that is only 20 inches in? Will it began to early flower since we only have 14 hours of daylight or so now? Or should I leave it out and let it keep going outside. Not sure what to do. Don't want to end up with a small flowering plant. Any advice would really be helpful. Thanks. It has been inside under the lights now an HLG 135w for two days at 18 hours.

Could always just keep her in veg and take some clones from her in the winter for next season.

No clones..just keep myself in a perpetual grow state. That way I don't have a thousand seeds backed up from my purchases. Anyways...still looking for an answer to my question.