I'm Black (well mostly anyway) and 5'8" and I love to wear vk inspired clothing.
Your skin color shouldn't be a factor in what style you wear. You can still wear lolita and make it suit you. Like other posters said, choose colors that compliment your skin tone and due to being tall you probably will have to go with custom made dresses.
If you really like the Lolita fashion then I say go for it. I've seen girls with skin tones ranging from very pale to dark skinned that pulled the look off extremely well.
As for the ganguro look, I say look into gyaru styles. I know tons of Black girls who wear gyaru styles. Ganguro is kinda outdated fashion of gyaru and not many wear it anymore. The updated version of it would be Manba. I don't know much about gyaru fashion but these sites can help you out:
Different types of gyaru fashion:
The Gyaru Handbook - Styles
Site and forum for those who wear gyaru:
Shibuya 109 at Ricoche.net
Hope this helped and sorry for the uber-long post xD