His powers might not be affected at all. Percy's connection to water is more about his essence as a demigod rather than his physical form. So he could still control water, summon sea creatures, and heal himself with water just as well as before.
It's possible that his powers could be affected in a more psychological way. Percy might be more hesitant to use his powers as a girl, either because he's not used to his new form or because he's worried about how others will perceive him using his powers as a female. This could lead to some interesting character development as he overcomes these insecurities and learns to embrace his powers again in his new form.
On the other hand, there could be some differences. Maybe as a girl, his powers could be more in tune with the more gentle aspects of water. For example, instead of just using water for combat, he could be more adept at using it for nurturing things, like making plants grow faster with water magic. This could be because Aphrodite's influence in turning him into a girl has also added a new dimension to his powers.
His powers might not be affected much in terms of strength. However, the way he uses them could change. For example, his web - slinging might be a bit more graceful in his female form. Maybe his spider - sense could be more attuned to different things now, like more sensitive to emotions or subtler threats.
His powers would likely be severely limited. The Sharingan, which requires a certain level of mental focus and chakra control, would probably not work as effectively. As a baby, Sasuke's chakra system is not fully developed, so he might not be able to access the full potential of his powers. He might only be able to use the Sharingan in short bursts, like when he's really scared or in immediate danger.
It's possible that his powers would be more erratic. As a baby, he doesn't have the control he has as an adult. So, his ice - making abilities might go off randomly. For example, he could accidentally freeze the water in a nearby pond just by being near it while having a little tantrum. But as he grows and learns about his powers again, he would start to gain more control over them.
His powers might be affected in different ways. For example, his web - shooting ability could be less precise. Since he's a baby, he doesn't have the same muscle control and coordination as his adult self. So, the webs might come out in a more random direction.
Percy's powers as Aphrodite's son would be very distinct from his Poseidon - given powers. He could possess the power of persuasion in matters of the heart. For example, he could convince two feuding parties to make peace by appealing to their love for something or someone. He might also have the power to make love last longer or end more gracefully. His powers would not be about brute force but rather about the subtler forces of human emotion and attraction.
If Percy is thrown back in time, his powers could be enhanced. In the past, magic and the power of the gods were more prevalent. The very air might be charged with more divine energy. His ability to communicate with sea creatures could expand, as there could be species that are now extinct or have evolved in his own time. However, he might also face limitations. For example, if he goes back to a time when the gods were at war, some of his powers related to Poseidon might be restricted depending on his father's situation in that war.
His water - based powers might be affected in different ways. If he goes back to a time when the oceans were less polluted, the purity of the water could make his powers stronger. However, if he goes to a time when the gods were more in control of the elements, they might be able to limit his power. For example, Poseidon might have more say over how Percy can use water powers if they are in the same time period.
His powers would be a blend of two very different deities. While still having control over water like the original Percy, he might be able to use his Aphrodite - related powers in combat. For example, he could use his charm to disorient opponents or make them more vulnerable. Also, his connection to the sea might be different. Instead of just controlling the water, he could perhaps make the sea seem more alluring or beautiful, which could be a new form of defense or attack, luring enemies into a false sense of security.
Annabeth would probably be quite surprised at first. But then she'd be understanding and try to help Percy adjust. Grover might be a bit more flustered, not really knowing how to act around a female Percy. Some of Percy's other friends from Camp Half - Blood could be shocked and might need some time to get used to the new Percy.
Aphrodite's power of love and beauty could potentially charm or influence Hephaestus' creations. For example, she might be able to make his mechanical beasts become docile or act in unexpected ways by using her love - based powers. Hephaestus' power of creation and forging could be used to create items that either enhance or counteract Aphrodite's powers. He could make a shield that protects against her love spells, or a weapon that can disrupt her control over love. Percy, being in the middle, might find himself affected by Aphrodite's charm but also use Hephaestus - made items to resist it.