Hey TT
As everyone else has said, welcome!!
So just give it a go! If you have an idea you've always wanted to try out, go for it. I would echo Pam's advice about spelling and grammar: if you think you have problems there, then by all means ask for help. Plenty of us here have experience of being beta-readers, and would help out if asked in relation to that and with plot issues, if you like.
And, as you've probably seen, we are also avid readers - so once you've got your story ready to show people, then
post it!Welcome again - have lots of fun!
Wendy