Toddler not walking

I’m getting really discouraged. My son will be 15 months soon and he won’t walk by himself.. he knows how to do it he just won’t do it in his own. As soon as we let his hand go he just sits down.

Any tips?

I know people say that it’ll happen when their ready but I don’t get why it’s taking him so long:(

Any other toddlers still not walking?