Information on first planets formed in the universe

[Cosmo Novice]

Can anyone give me a rough idea of a timescale for first planets in the Universe?

I understand that supernovae are required for heavy elements for rocky planets such as mars or earth, but was wondering if this same requirements would hold for gas giants?

Just trying to establish the most likely oldest planetary world types. Also were the first generation stars supposed to be larger so would this effect planetary size and composition?

I am just trying to get a clearer image of the early development of star and planetary formation so apologies my questions are not particularly well formed. I am mainly looking to extend my mental image of expansion and development of the early matter U.

Thanks

[Nik_2213]

IMHO, you would get a range of 'pure' gas-giants formed along with the first stars. However, the 'Brown Dwarf' variety might not get a chance to burn through their lithium before they were blasted by nearby supernovae. Without rocky cores, even they'd just evaporate...