Cool man, glad u choose to try growing it for her.. Oh fuck yea its easy to tell, but if its a hybrid than its much harder. That when u bread your strain outside its own genotype, its when u bread your plant and not back cross it to its self. Yea fucking tomatoes. I know someone who has never grown shit, but grew some tomatoes no problem. The thing is, its really about the environment for them.
Unlike a pot plant,it generally produces but can produce fuck all too under a rough grow environment. The plant will still run it's course. I never fucked with them since I am pretty damn young to care about them lol. BUT, this year my gf wants to grow potatoes, green onion, tomatoes, chives (same thing)? and something else. Best luck man!