It depends on the academic career you find most desirable. Although GEDs are supposed to be equivalent to a high-school diploma, many people consider them inequivalent. If you want to get a Bachelor's degree (or more advanced), a high-school diploma would make the process easier since you could apply to the university straight away. If you choose to go for a GED but still want to go to university, there's a slim chance you may be accepted, otherwise you would have to go to a college or community college for at least 2 years, then transfer to a university.

Keep in mind, with online courses, you are limited in the areas which you can study. For example, if you wish to do biology, chemistry or physics, you could learn anatomy, physiological processes, underpinning of chemical reactions, stoichiiometry, physics theories and so forth, but you would be unable to perform hands-on experiments. In first-year university for these courses, you're not expected to have a lot of experience with the lab equipment, however, you are expected to have a bit of experience with basic equipment as well as how to properly interact in a lab with classmates.

On the other hand, areas such as math, some phyiscs, computer science, history, etc... don't require lab work.

If you don't have an area of study that you love and know you want to study in, that's not a problem. From personal experience, most people who I know/knew didn't have a solid idea on what they wanted. Those who did frequently changed to something else.