the ai cannot colonize at this stage of the game, so theres no danger. take into account the whole solar system it's in is there any higher hazard planets with exploitable resources? what about a lesser planet but it has ruins? also is there stable locations for buoy placement? i personally don't like to spread my colonies out too much but some locations are just too valuable to let slide, but i leave those for later. don't fall for the first low hazard planet you see, you can find your garden of gaia with some searching. Number three: take the time and explore as much of the map as you can.
pirates will also see your fledgling colonies and attempt to raid them, so you'll need to be ready to rock from week one. as the new kid on the block, factions will raid you as you start taking more market space for your goods and these fleets will not hold back. you should, at minimum, have a solid cruiser ship as your flagship and a fair fleet of similar ships. While you grind the capital and resources you'll need, you also should invest in all the skills that help colonies, such as industrial planning and planetary operations. upgrading the constructions on your new colony are also very pricey, tens of thousands of credits for basic ones and upgrades get more and more expensive as you climb their trees.
for one, it's a big investment: 1000 crew, 300 supplies (i cant remember the exact amount), 200 heavy machinery. I love the colony mechanics and i like having my own pocket of space but my protip: don't feel you need to be in a rush to do this.