Yep - seasoned uke player here - I have several, and a uke banjo

more details on my blog (google GOT A UKULELE)

Keep at it, its a great instrument

Funny typo there, as 'of' is actually dutch for 'or' :D.
Welcome!

I play Ukulele. It's alot of fun I must say :)

I want to learn the ukulele. What should I start with? Can I do it by myself or do I need a teacher?

There are indeed some excellent online lessons available on YouTube, which I believe are the easiest way to gain some basic playing skills. Once you've got the hang of the basics, you can further enhance your skills by checking out ukulele strumming patterns online. Practicing these patterns on a daily basis will help you develop your rhythm and technique, gradually improving your overall playing proficiency. Additionally, exploring different styles and techniques through online resources can add depth and versatility to your ukulele playing repertoire.

I'd start with a Tenor Ukulele if I were you. Rich sound compared with smaller ukes and a manageable size. I favour the Kala brand but you may find them a bit pricey. It depends on your budget and you may want to start with something cheaper to start with in case you decide it isn't for you.
You can definitely teach yourself and if you get serious, look at perhaps getting lessons. I look at You-tube videos.
Matt Dahlberg and Marco Cirillo are top notch IMHO, but there are many others.