cockatiels are lovely companions. i have 2 and i enjoy them immensely.
you asked if they are beginner birds, and they sort of are. for example:
-cockatiels are less known to pluck their feathers. (it's not unheard of though, that it also doesn't mean they are not under stress)
-cockatiels have their cute crest which can help you asses their mood immensely. they also hiss when they are scared which is a good indicator.
this video explains a bit about cockatiels and especially about their crest and body language.
-cockatiels originate from australia, and over there their diet mostly consist of seeds. fresh green seeds and dried brown seeds. so in your home a cockatiel can have 30-40% of it's diet made up of seeds, and the rest veggies and pellets.
- cockatiels are short lived compared to other parrots, the longest living one being 32 .
all of these make cockatiels a nice introduction to having birds as companions but it in no way diminishes the care they need.
some things to consider:
expenses:
-a large flight cage for the bird or birds. most users buy
this one
-accessories and toys for the bird. those need to be replaced as time passes because birds love toys they can chew and destroy. another good addition to the cage are natural branches which you can purchase or make yourself, which are very healthy for their feet.
-annual vet check ups and emergency vet funds. you should check how much a visit to the avian vet near you will cost.
-food. birds need to have a diet consisting of good quality pellets and seeds and fresh fruits and vegetables.
will you or your parents be paying these expenses? do you have enough or are your parents willing to spend this much? a thing to consider.
you said you go to school so you can spend a lot of time with your companion, and indeed cockatiels are very social creatures. if you'll own a single cockatiels it will need interaction from you to stay healthy and happy. but you still should provide enrichment for it for when you are away . things like foraging toys, a playing radio and lots of toys can help it pass the time until you are back from school.
this schedule can work for now, but what about later? are you planning on going to college or moving out of the house?if so, the cockatiel will limit your choice of apartments, as not all allow pets.
if you'll decide to leave the bird with your parents, will they know how to take good enough care of it? how about interacting with it?
this is a very important thing to plan to, as many cockatiels lose their homes and are sent to shelters because the owners can't keep them anymore in a new home.
do you do chores around the house? as fun as they can be birds are a very big chore
waking up early and preparing fresh food for them, cleaning their cage and surrounding area, refilling water and food dishes every day, deep cleaning the cage once a month, spot cleaning daily are all things that will need to be done for them to be healthy and happy.
if you really want a cockatiel, research research research!! look into every aspect of having a cockatiel, see what problems come up and how you can solve them so your future companion will have the best life possible.
some places to look into:
animal wonders on youtube.
flock talk on youtube.
flock talk blog.
talk cockatiels stickies.
ask bird bloggers. and of course the stickies in this forum! in the cockatiel, toys and cages, enrichment and food subforums.