I'm really nervous to start!

So, this is really awkward to post and I'm sorry if I'm taking up anyone's time, but I've been masturbating for a while now, yet I'm still too nervous to do much else than rub my clit. I'd really like to try something more, but I'm not sure what, and I'm also really nervous as to messing up somehow? I'm only a few months off of fifteen so things like toys are out of the question, and I'm way too nervous to buy lubricant or ask someone to.

Can anyone help? The things I've been trying to work up to doing are fingering and that thing with the showerhead, but I'm not really sure how to do it.

Sorry, for someone almost 15 I know I should probably know this stuff already, but I've been too embarrassed to even google it so far.

Thank you so much for anyone who takes the time to read this!