Flower after transplant??

Is there a time frame I should wait after I transplant my veg into bigger pots before going into flower?? I was previously told I need to wait 7 days after transplanting to send them in...

you do not have to wait at all. Root growth slows significantly in flowering, so it will likely not fill the pot with roots if you flower right away. And it wil not get as big in general. It is also good to note that if the plant is not rooted, you can have watering problems..... I think this happened to me, had it in a 3 gallon but I do not think it was fully rooted and I overwatered (watered it the same as my others in 3 gallons).
So, its up to you. The more veg time, obviously, the more yeild and the better rooted your plant will be. Id say wait at least a week, if not two. Patience virtue ect. ect.

The plants are about 4 feet tall, they've been in veg for 2 months or so. I transplanted them from a 1 gal to 3 gal before putting into flower but someone told me after transplanting I need to wait 7 days before putting them into flower and Im not sure why but just wanted to check.

it is a good idea to wait at least that long, to let them root in the new pot. Id say 7-14 days, whatever you can wait for. Have you topped them?? if space is an issue top them and wait 2 weeks for the roots to grow and the two colas to grow abit......

Space is not an issue, but no I haven't topped them... Ty!