Are my plants big enough to put into flower

[Cjdennis420]

Hey growers this is my first grow and a friend gave me some mystery bag seeds and tbh there not doing so well and there growing super slow and I have limited space to grow and I wanna get the plant some higher quality seeds so I was wondering if I could put them into flower even though they are only 8 in tall and 3 1/2 weeks old I have already topped and low stress trained them the new main branches are around half a inch tall is it to early in not how much return should I suspect to get I have 5 of them.

 

[Ossi Ossi]

Some pics and more info would be beneficial
Peace

 

[Cjdennis420]

As you can see they aren't doing so well I left for around a week and it got really hot in the mid to high 90°f so I just want to harvest them asap

Some pics and more info would be beneficial
Peace

 

[Bigbud78]

You need to get that plant healthy before entering flower stage so I'd say at least a month for that plant to produce anything of substance