我需要在R中组织两个ggpolt条形图，以便它们都从同一个月开始？

# 导入所需包
library(ggplot2)
library(dplyr)

# 创建数据框
data <- data.frame(
  month = c("Jan", "Feb", "Mar", "Apr", "May", "Jun"),
  category = c("A", "A", "A", "B", "B", "B"),
  value = c(10, 15, 20, 8, 12, 18)
)

# 转换月份为因子并按照月份排序
data$month <- factor(data$month, levels = c("Jan", "Feb", "Mar", "Apr", "May", "Jun"))

# 组织第一个条形图
plot1 <- ggplot(data, aes(x = month, y = value, fill = category)) +
  geom_bar(stat = "identity", position = "dodge") +
  labs(title = "Bar Chart 1", x = "Month", y = "Value") +
  theme(legend.position = "top")

# 组织第二个条形图
plot2 <- ggplot(data, aes(x = month, y = value, fill = category)) +
  geom_bar(stat = "identity", position = "dodge") +
  labs(title = "Bar Chart 2", x = "Month", y = "Value") +
  theme(legend.position = "top")

# 将两个条形图组合在一起
combined_plot <- plot1 + plot2

# 打印组合后的条形图
print(combined_plot)