If there is a garment you can imagine, you can make it. If you cannot currently make it, you can improve your skills to make it.
Simple things like tshirts and pants are often not worth it. There has been so much industrialization that you can buy those things cheaply.
But more specialty items can be worth it.
At least you get the skill of making it as well.
You should absolutely start with more technically simple projects. Do not think you are going to go from never having sewn to making a complicated custom garment.
Start small, start simple, take on interesting projects that help build your skills.
Be more proud of things you made, rather than things that you purchased.
By making things, you are improving your ability and skills. It is easy to buy things, all you need is the money to do it.
Making something also gives you a better appreciation and understanding for the thing.