I saw this post, thought I responded, but didn't.
I agree with the above, though, I would argue that it's more leaning to a soft polytheistic view of things which you do not need to have. I am not saying it's wrong, I'm saying it's not the only option out there.
I agree with the opinion of researching their religious practices and cults, the culture, and then the myths associated with them. If you do syncretism, honor them through the way that particular deity would be honored. Minerva and Athena are an example of syncretism. But, I would honor Minerva like the Romans did, and Athena as the Greeks did. This is just one option; there are others.
I agree, you do not need to make any oaths or formal dedication at all until you are ready. You need to consider all of your options before committing to something like this.
Personally, I would say you will not be offensive provided you respect the way each Goddess wants to be worshiped, both historically and later through personal experience.
For Aphrodite, the poetry of Sappho is a great look into the way one ancient viewed their relationship with Aphrodite. Another fun thing to look at is ways which Aphrodite expresses herself in your area. For me, polytheists in my area love to see her as the Goddess who landed in the Gulf; the one who is lead on of carriage of egrets and herons.
Traditionally for Greek worship, you physically bathe yourself. Then, take a flame (a match or burning bay leaf) and put it in water. Wash your hands and face in the water, clearing your mind. Take a bowl and a cup to pour and say a hymn or praise to Hestia. Then pour the libation to her. Now, turn your attention to Aphrodite. Introduce yourself, offer a libation, and talk to her, and all that goods stuff. Libate again to Hestia and you are done. The libation usually is mixed wine, but you can use anything you drink, such as koolaid, soda, coffee, water, anything.
"Hellenismos" or "Hellenic Polytheism" is the term for modern worship of Greek Deities.
Hope this helped. Good luck!