Why won't my 20 yo sister grow up!?

she has a 1 year old son, and she is just making me crazy because she will come over everyday and feed her son and change him then when she leaves i have to go around and pick up dirty diapers and clean up the high chair, her and her boyfriend have been eating here almost every night for the last week, and she sat there COLORING while i did half the dishes and then she finally helped me with the rest, and another example, is we had a fire outside and we were all standing around the fire and my sister was out riding my 8yo son's bike, am i being to hard on her??
she has always been a complete "tomboy" and she talks about working in her shop when she buys a house and i told her she really needs to throw in the grease rag and pick up a dish towel. I have tried telling her things like this thinking maybe she will get it, but she hasn't. Her and I are very close but her immaturity is driving me crazy!!!

the whole reason for this vent session, is she gets mad at me because i want to stay home and clean house instead of doing whatever it is she thinks we should do that day which is usually something i don't care to do.
does anyone else think this is immature or am I being hard on my lil sis? and do you think she will ever grow up!?

You really need to set some personal boundaries in your life... Your sister shouldn't be "allowed" to come into your home and mess it all up, then leave as if she's not responsible to take care of diapers and other messes.

And if you don't have enough time to yourself, and would rather she came over when it was more convenient for you, then let her know. You aren't responsible for entertaining her every day.

You and your sister are also individuals. So if she wants to work on cars or whatever it is she does, then so be it... that is her choice.

However it's YOUR house, and you really need to expect others to respect your home -- setting boundaries and limits with others isn't being mean, it's all about self-preservation.

I think that you should sit down and talk to her and Let her know how immature she is being then I think that you should pray to God to help you

I think you are typical sisters! You clearly have different interests and that is fine you just need to find a middle ground. Is her son well cared for, clean, fed, well loved? Do her and her boyfriend have jobs and their own place to live? Why is she feeding her son and herself at your house but more importantly why are you allowing it if it bothers you so? The bottom line is this if she is intruding in your life that is one thing and you have the right to tell her you do not want her eating your food and trashing your house. However, her life is just that her life, she has every right to decide what to do and how to act. I will make one very important caveat to that statement if she were putting her son in danger or neglecting him you have every right to step in but unless that is the case you my dear need to butt out.

she had a kid very young. basically she's still a child herself. she didnt let herself even be a child and enjoy her age and freedom. now she's 20. you think its bad now wait till she can legally go to bars and drink. Im sure at least for that entire year she will probably spend plenty of time doing that as long as she has someone who allows her to push her child onto them. see when people have kids at such a young age everyone wants to be helpful but most of the time they dotn realize that by caring for helping care for the child they are actually hurting the situation because she doesnt have to learn any responsibility or take credit for her poor judgement and actions!

chances are she will probably be immature for a long time since she now has to be immature between being a caregiver to a baby. if she wants to own a shop thats her choice. you shouldnt give her greif about that. some people enjoy working and doing hard labor and making something for themselves. its certainly not a bad thing considering the divorce rate and the amount of single mothers who are on welfare because they never chose to get an education or find a career path for themselves just in case a man left them and they were forced to go it all alone!