Plan first, then Smallville.

As much as she hated Superman, she loved power, and she knew if she could control Superman when he was just Clark Kent and not Superboy or Superman.

She figured that once she had control over Superman, she could become even more powerful than her father, but she had to be careful, she didn't want to effect her past and do something like not be born. Also if she let Clark become Superman while still under her control, once she started using him for evil, no one would suspect it. The thing was that the problem was how to control him, would she seduce him and make him love and need her, or beat him to the point where he was afraid of her.