Aston Villa is more like a fluke they can able to win against Bayern Munich and reach 5th position in Premier League. Currently Aston Villa only have good results, but their statistic are actually just like a mediocre teams. A strong teams need to have both good results and performance, Aston Villa don't really dominating the match and they have bad goal/conceded ratio.
Chelsea on the other hands, have both good results and performance, so I will not be surprised if Chelsea will qualify for Champions League in the next season.
Chelsea have shown quite good quality so far at the start of this season. In fact it exceeded everyone's expectations. And it looks like Chelsea can indeed surpass Aston Villa in their achievements this season in the Premier League. But Aston Villa have really improved a lot since last season. Last season Aston Villa managed to finish in 4th place because of their consistency towards the end of the season at that time. And it looks like their good performance continues to this day. In the UCL they beat Bayern quite well. And in the Premier League they managed to hold Man United to a draw. With quality like that, I think the competition for tickets to the UCL will be very fierce between Chelsea and Aston Villa. But last season, many changes often occurred since the middle of the season. And I think this season something similar might happen. So we can only make a more definite assessment since the middle of the season. because there will be many changes starting from now until the middle of the season.