Does it just take time, or is there somthin else I need to do? Super dumb question, but so am I.

Don't say you're dumb, that's mean (to yourself)!

Yes it is over time, though nurturing makes it speed up a bit (I think it was something like 6 nurtures makes an hour).

General:
Pets age at 1 hour per hour

More:
freshly bred Eggling > Hatchling at 72 Maturity Hours (3 days)
Hatchling > Adolescent at 216 Maturity Hours (6 days from hatching)
Adolescent > Adult at 648 Maturity Hours (18 days from start of adolescence)
Maximum Total: 27 days

Maturity hours is a bit different from Real-time hours, since it can be modified
Egglings gain a bonus Maturity Hour for every 5 (or 6? I'm not clear on this) correct nurtures

Hatchlings gain +1mh for every 4 correct nurtures (and +1 to their lowest stat every 8 correct nurtures)
> Magical Pie can be used on a Hatchling to double the effect of nurtures (every 1 nurture now counts as 2; 2 correct nurtures to +1mh, 4 to +1 stat, double scale payout per nurture)

Adolescents gain +144mh if a Magical Pie is used on them (72 hour cooldown, meaning a max of 2 Magical pies can be used per pet, skipping 288 hours (12 days) of adolescence)