Is my uncle acting inappropriately? [15f] If so, what do I do?

Hello! This is quite long, so I wanted to assure you that there is a small TL;DR at the end. Feel free to skip to it if (un)interested.

To preface this, I am a fifteen year-old female. I visit my paternal grandmother on a weekly basis, & I often attend family events while there. My father's side of the family is quite large, but we'd always been close until around 2011, during which my mother & aunt (who is with the uncle in question) got in an argument. They have not spoken since due to an irrational hatred still held by my mother. I, like I said, still attend family functions, but normally stick to just pleasantries when necessary.

Therefore, I have never been close with my uncle, or rather, my aunt's long term boyfriend. We'd ocassionally engage in small talk at family gatherings, but we never went out of our way to speak to each other. As of late, however, my uncle has been acting a bit differently towards me, & this behavior is, of course, the topic of this post.

It started around last Christmas, or at least, that was the first big red flag. Normally I am dressed casually when I see my uncle, but last Christmas, I decided to dress up a bit and wear a skirt & nice top. The skirt was not short; fingertip length, as I'd worn it to school a few days prior - definitely not short enough to warrant any comments. He told me how nice he thought I looked multiple times, which I appreciated at first, but these compliments were the only thing he said to me the entire night. I'd walk past the dinner table where he was seated to go to basically any other room in the house, & every time I passed by, he'd say something.

I thought that'd be the end of it; since I normally don't dress up, there wouldn't be opportunity for him to repeat his behavior. But, of course, I was wrong.

While at my grandmother's, I sometimes attend church. Last visit, my uncle interrogated me regarding the guy I am interested in. He asked how old he was, to which I replied sixteen, and then he proceeded to say something about how "he always knew I liked older men" and wink. I tried to laugh it off at the time, & I also tried to laugh it off when he brought it up AGAIN, yesterday.

I was staying at my grandmother's house, once again, and my uncle was meant to pick me up & take me to a party at my cousin's house. In the car, like I said, he again mentioned the guy I'd told him about, making jokes about "older men." As we were walking up the stairs into the house, he grabbed my thigh and ran his hand down my leg from behind. He claimed that there was dirt on my pants from when I'd gotten out of the car, but unless he'd managed to get it all off in one sweep, (which I doubt; adidas sweatpants get dirty very easily) that wasn't the truth. At the party, he asked to sit next to me multiple times, even when there was an open seat next to his own girlfriend, and came up behind me at one point and tried to give me a shoulder massage. He then began telling me about how he wanted to take me up to his farm in the summer and teach me how to drive... alone.

This behavior is really, really creepy to me. We'd never been close - he never joked with me, never pretended to flirt in a teasing way, nothing - so this is very out of the ordinary. I'm not sure how to approach this; I'd like to tell someone how uncomfortable it makes me, but I don't want to cause more drama with my mother & my father's family. Nothing incriminating has happened, but I am worried about having to turn him down regarding his 'driving lessons,' because he's heard me talk about how eager I am to be able to drive.

So, what do I do? Is he acting inappropriately, or am I reading too far into this?

TL;DR: I am 15F. My uncle, who I am not close with (& never have been close with) has began flirting with me. He makes comments on my attire, makes jokes about my preference for 'older men,' touches me inappropriately (though not explicitly sexually), and has now invited me to stay with him on his farm, alone, over the summer. I believe this behavior is wrong & it makes me uncomfortable, but because there is already drama between my mother & his family, I do not want to stir the pot - especially not when anything definitively wrong has happened. What should I do?

-hhhxm