Hi jaylynn ... I'm a new grad nurse who graduated from a diploma program earlier this month.

I hope I can give you some meaningful info.
You are correct that ADN, diploma and BSN nurses all take the same NCLEX and start out as entry-level RNs with the same amount of RN experience - zero. Their entry-level positions in hospital settings are the same. Some hospitals pay a nominal amount more to those who have a BSN, many do not. So no, there is no dungeon of low-paying jobs relegated to us diploma grads ...
Advancement opportunities vary greatly, and depend on many, many things, including education.
Only you can decide what's right for you, but if it were me, I'd start sooner rather than later - at the diploma program.
If I can give you any further info feel free to send me a PM (private message). Welcome to allnurses.